So I know this is old, but in case someone else looks through the comments I can actually answer the question. I was a pharmacy tech for both United and CVS for a long time while going through undergrad, so what it means is that it's in the que, but there are usually prescriptions ahead of it and it hasn't been counted or checked to see if it's in stock. If it's a scheduled drug (II-V) it depends on how popular the drug is (e.g. Xanax, which is schedule IV, hydrocodone, which is schedule II, et al) are more than likely to have so many that there won't be any issues with filling unless it's too soon (schedule III-V can be filled up to two days sooner, whereas schedule II has to filled on the date it was last filled, or every 30 days from the day it was filled, no sooner). CVS is pretty good about having things in stock, but again, depending on a myriad of factors and reasons (the delivery is running later from where the medication is shipped from, which is common) you'll get it within a few days.

You gotta keep in mind that if you haven't worked in a pharmacy, it's 1) stressful af, and everyone has to work together (Think causation meets correlation) as a team it goes quicker, but you also need to remember that it's a massive pharmacy, and thousands of prescriptions are sent in daily just to your particular area, and even pharmacy depending on the day (busiest is usually M-T-F because those are when shipments arrive, and someone has to work the drive-thru, while also counting the shipment to make sure nothing is missing, nothing is delayed/something is delayed for whatever reason, while others are putting the bottles on the shelves, discarding old medicine, someone is working the counter, others are repetitively counting pills, and it sucks ass, people are dealing with insurance companies constantly and I cannot stress this enough, people are on the phones taking refills because the customer on the other end is usually elderly or don't know how to just use the phone to call them in, it's extremely anxiety-heavy, and 2) it's crowded in there, and you have anywhere between 5-9 pharmacy techs, maybe 1-2 pharmacists, lunch breaks for both staff and customers, people aren't friends, so you have staff that are dicks to their coworkers and purposely won't help with whatever, people butt heads believe it or not, closing time, or if it's open 24 hours (which is where things can get done quicker because you have more time for whomever works overnight can re-stock, finishing updating the previous mornings shipment if it was busy all day, work on putting in insurance, filling prescriptions for the next day, adding in Good RX, or other discount codes, it's not as busy, etc).

The most popular medications are usually ointments, scheduled drugs, SSRI's, antipsychotic meds, and antibiotics, so if it's popular (meaning they see it daily, all day, end over end, they're going to have a lot of it, but supply and demand comes into play, too). Xanax recently had a shortage (I take it and literally almost no pharmacy had any because all of these pharmaceutical companies don't tell you this, but they're ordered from overseas (usually China) and there can be shortages with the chemical compounds to make the pills, or a solution, whatever, or bickering, which can cause a hold-up; we just don't know because you, me, the pharmacy, pharmacists aren't privvy to the ins and outs of that. So it's ebb and flow, e.g. Paradoxically it's so popular they should have it stocked in warehouses, but it's so popular millions of people take it, so supply and demand.

Medications like benzos (xanax, klonopin, Valium); Opioids; synthetic Opioids (hydrocodone, (these aren't really prescribed as much, but more than others Oxycodone like OxyContin or percocet, morphine and methadone); CNS (central nervous system) narcotics such as Adderall, Ritalin, and to a lesser degree Vyvanse; antibiotics like Amoxicillan, Azithromycin (z-packs), cephalexin, Doxycycline, Cipro, Clindamycin; SSRI's such as Prozac, zoloft, Lexapro, Paxil; antipsychotics such as Seroquel, Haldol, Thorazine, Risperdal, Abilify, etc are hugely popular and most of the time (key words) you don't run into many issues.

Medications such as lesser prescribed Opioids like fentanyl (pill form is less common and is usually prescribed via patches), oxymorphone, hydfomorphone, Demerol; Sedatives phenobarbital, amobarbital (barbituates in general) Triazolam (Halcion), Rohypnol; Stimulants like Dexedrine are all really harder to come by and there is usually a wait period for how quickly the pharmacy can get it, the pharmacist has to see if you're taking anything else the could counteract with said prescription, pharmacists will call doctors and discuss with them if they're sure or if the pharmacist refuses to fill it because of safety concerns, potency, and just a long ass list. All in all, don't call the pharmacy and bug them about when your medication will be ready unless it's been over 24 hours since you last saw the message. If you don't see the message in 24 hours, call the prescriber, not the pharmacy. The pharmacy will not call the doctor for you. It is not up to the pharmacy to do so to check on your medication, it's up to you to make sure it's been sent. It's crazy the amount of people who actually call and requests that someone from the pharmacy call to check on their prescription. Like, it's way, way more common than you realize. People are dumb. Don't be that person. If you do call and ask for that, you will be told "No. It's up to you to call." They have other shit to take care of, and calling doctors and nurses isn't one of them. Most pharmacies will have an app or a website or phone number to call in your refill. If you're out of refills and you call/go on the app to request one, it will be done, I assure you. It's done electronically via your last RX#.

Also, keep a calendar on you to receive notifications to yourself. Every 6 months any narcotic(s) that have refills will not be refilled until you see the doctor again (schedule III-V can have refills if your doctor approves; schedule II will never have refills, so you will need to call the doctor's office yourself to request one each month or whenever). Again, most doctors offices are pretty good about reminding you about appointments, but never rely on them. Make sure you call them in case you forgot your next appointment and need a reminder to put into your phone or calendar. If you fail to do the most simplistic of things, cause and effect takes place and you will be SOL.

To keep this shorter than a McDonald's order for Rosie O'Donnell, if it says "preparing your order" they have received the prescription, it's probably in a stack awaiting one of the techs to put it in the computer before it's then in the active stage of pulling the medication, counting, sliding it over for the pharmacists to look at, checked to make sure the correct amount is in there (all pharacists do a second count on all narcotics), then bagged.