What do you do work wise? It could also be affecting it. Doctors usually treat the symtoms and not the cause. Pain killers just mask the problem. You’re better off seeing a physio.
Took me 18 months to sort mine. Everytime I started to make progress I would get a relapse. I could have sorted it quicker if I had rested it more and started with the exercises sooner. The trick was to strengthen the muscles without over working them. Definitely worth visiting a physio for advice.

It’s very much a bike fit issue. I’m almost certain that the handlebars are not in the correct position. They need rotating but I can’t possibly determine where to. They are flat bars with a backsweep. I just can’t work out how to get the right backsweep and I can’t find any info on this.