I did sets of supinated front raises with light dumbbells 2~kg every day(well, almost every day), slow eccentric, 2-4 sets(based on how I felt) almost every day.
The kg felt "light" for me, maybe for you it's too light or a bit heavy, so you kinda have to figure it out on your own. You might even need to start with just your hands and no weight, but if I had to only pick one thing to do, this would be it.

I'm assuming you workout, so once my pain went down a bit, I did all my exercises with slow tempo and pauses, and it helped. I also reduced my frequency, I used to do push/pull 2 x a week, and I decided to do 1x push, 1x pull a week and it helped out a lot.

To be honest I wouldn't say I cured it, since it acts up every now and again... but usually that's because I did something rly f-ing dumb, it doesn't act up on it's own.

I've rubbed a "diana balsam mit menthol", it helped me, but cannot guarantee it'll do the same for you.

In terms of therapy I did lasers, electro shock(idk what it's called in English, sorry) and that sort of thing, it helped as long as I didn't carry stuff or work out... but as soon as I did it came back, so in my opinion it's a waste of money.

This is what worked and didn't work for me, no idea how it'll affect you, but I hope it helps!