Hi Hans,
I suffer from the same thing from time to time. Mostly because of kind of work a do and lifting weights (bodybuilding). I have great respect for Athlean-x on YouTube. Simply because I am Physical Education teacher myself and know quite a bit about human body. This guy is very good and his videos might be helpful for you too.
https://youtu.be/r7Arz53_f3c
https://youtu.be/qTjDq3_D-FU
https://youtu.be/7kTNk3qEuLM
Don’t be confused that those videos are about lifting weights or about people who have sports injuries. The fact is tennis elbow and many other injuries are caused from overuse or weak muscle, tendon or ligament. Instead of “masking” pain with cortisol injections or rubbing various creams the best and most of the time permanent fix is to make it stronger.
Cheers
Bob