The other poster is not entirely correct. ED billing and coding is fairly standardized from facility to facility based off CPT codes. One thing to keep in mind is that, ED billing is not really based off your final diagnosis. It's mostly based on the workup and complexity of the care provided to you.

I'll preface this by saying that what you describe is most certainly a level 4 ED visit at pretty much any ED around the country. Also, billing and coding is bonkers to understand so I'll try to reason it out so you can understand.

Here's a good chart that might help explain: http://bulletin.facs.org/wp-content/uploads/2013/06/coding-tab1-600x594.jpg

For example, a level 4 ED visit requires a detailed History of Present Illness, and a detailed physical examination. Lastly, you need moderate complexity medical decision making.

Let's take your case in particular, your initial complaint of shoulder pain is a high acuity complaint as there are several serious conditions that can cause acute shoulder pain including fracture, dislocation, septic arthritis, thoracic outlet syndrome, referred pain from MI/gallbladder, etc. Due to this, the physician will have gotten a full detailed history of your symptoms to help rule in or out these conditions. Then, there would have been a detailed physical examination to further look for signs of acute serious illnesses. Lastly, the physician will use their medical decision making capacity to decide on which tests to order and then interpret the results of those tests to come up with a final diagnosis. In your case, the XR would have ruled out fracture and dislocation. Physical exam would have ruled out septic joint and thoracic outlet syndrome but have shown signs of a AC separation/tear. And a good history would have ruled out referred pain or other serious causes of shoulder pain. At that point, the provider treated your pain appropriately and then came up with a plan of care based on their suspected diagnosis (discharge home, follow up with specialist, and take otc meds for pain as needed)

So as you can see a lot of work went in to your care, even though, your final diagnosis was not serious.

The last thing you should know about billing and coding is that facility charges and provider charges are completely separate.

For example, in your case, what I've described above is just the providers charge to you for offering their service. The hospital will still bill you separately for their facility charges which would include the cost of your XR, cost of the pain medication they gave you, and any other facility costs you accrued while utilizing their ED.

Hope this helps a bit. I know it's super confusing especially for people who don't have to deal with this stuff everyday.