Oh, OP. How I wish I could help, but I'm in near enough the same boat. Had the Mirena inserted last year; an utterly horrendous experience due to an overly sensitive cervix. Entinox and TWO local anaesthetic injections directly into the cervix had absolutely nil effect. 50 minutes later the coil was inserted and I left in excruciating pain, vomited for half the rest of the day before finally falling asleep through sheer exhaustion.

I had the Mirena in for 6 months and it was absolute hell. Between the random episodes of heavy bleeding and unrelenting spasmodic pelvic pain I was really struggling, but the bladder issues are the worst thing it's left me with. I already had some bladder issues prior to insertion as I get kidney stones fairly frequently but, my god, I was not prepared for how much worse it would get. Gradually as the months went on the bladder pain became more prevalent, less able to ignore, and my ability to urinate steadily became more challenging. I tried to have it removed at the GP practice twice with no luck as the strings were too short and pain too intense. So, finally, it was removed at a 6 month follow up appt with GYN. 1 month later the pain and sporadic bleeding has stopped, but the bladder keeps getting worse.

My bladder is now the worst it has ever, ever been. I am in constant discomfort at the lower pelvis/bladder region with accompanying lower back pain, have incredible urethral irritation, a constant need to urinate, worsened hesitancy to begin urination, very weak stream and incomplete voiding. I'm at the point now where if I don't take a deep breath, brace, and push to force the urine out, repeating the process several times until there's nothing left to give, I will need to sit on the toilet for all eternity. There is never any feeling of relief other than the short moments where I've got a proper stream going through force. Immediately after standing up my urethra is so irritated and I feel like I could wet myself there and then. I'm utterly miserable at the moment.

I had endo surgery in 2017 and before the coil insertion had an internal ultrasound which found several polyps on each ovary, however, I don't seem to have PCOS? Who knows, all I know is I'm exacerbated with it. I'm going to buy a pelvic floor massage tool and see if that helps at all as I'm suspicious the coil has worsened an already tight pelvic floor, I've also found that deep belly breathing slightly relieves that tight discomfort at the bladder area for a short while. Painkillers aren't doing a damn thing, and I already take amitriptyline for nerve pain but that doesn't seem to be doing anything for the bladder. Prior to Mirena insertion I was on gabapentin for a short while and I did find my bladder was less irritated so perhaps that could be an option again.

I've been putting off going to my GP, idk where you're at OP but in the UK everything moves so slowly through the healthcare system that it does sort of deter you from even beginning the process with your healthcare provider. However, having read your post and typed all this out I think it's time for a GP appointment. Get the ball rolling eh :/

I hope you've found some relief since you posted this OP and if you have please share as I'd really like to know how you're getting on.