Large knot in crease of elbow

Hi everyone!

Looking for advice here as I’ve sort of run into a dead end with my PCP and therapists. I’ve had a reoccuring “knot” show up in the crease of primarily my non-dominant arm, around the elbow. It occasionally shows up in my dominant hand, but not as frequently.

It usually is about ping pong ball sized, but gets larger if I try to massage it out. It’ll eventually leave for a few days, but then come back just the same as it was. It causes finger numbness (usually in my ring), and there’s some tenderness in the location itself, but little pain otherwise most of the time.

I have EDS and fibromyalgia, and my muscles as a whole are rather weak. I previously was diagnosed with tendonitis that never really went away. I use my arms frequently, but I try to counteract this with multiple compression braces, cold menthol patches, heat from a heating pad, stretches recommended by my physical therapist, and painkillers in attempt to get the swelling down.

My doctors and I are at a loss of what this is or what to do about it, so I was hoping someone else might be able to give me some insight!! I work freelance, and I can’t really afford much time off, hence the surplus of other means of coping. Resting too long honestly seems to make my symptoms worse, for some reason.