I've struggled with tennis elbow tendonitis off and on. It really hit me hard in 2022 when I was doing a construction project and using a hammer and nail gun often.  I went to the doctor at one point thing thinking I had a more serious injury and was put on a heavy duty anti-inflammatory for a few weeks that seemed to help some but what really helped me was deep, hard tissue massage of my forearms.  I learned to massage my forearms so hard it nearly made me cry and I would bruise my arm but the next day I felt so much better.  It has to do with breaking down scar tissue and inflammation.  I still have flareups on occasion mostly from holding on to a steering wheel when driving truck or the hydro handle when in the sprayer but it is much more manageable than it was in 2022.