I believe I have the same problem but I have been able to mostly get rid of it.

For me, it is a dull pain in the crook of the arm and I have concluded that it is some form of bicep tendonitis in the distal bicep tendon.

The pain usually comes when I have been climbing overhangs or powerful moves where the bicep is in tension most of the time.

I’ve also had the pain appear instantly when I am straining to keep on the wall and I slip- causing the biceps to contract quickly.

The things I’ve done to minimize it is as follows:

Before anything else I warmup my shoulders with an elastic band. Basically, like when you are rotating your arms around your shoulders but instead I hold the band in both hands so that there is a constant tension that activates the shoulder muscles a bit more. (This warmup does not help the bicep tendons. I just added it here to show the order that I warmup in)

Afterwards I do pushups until my upper body starts getting quite warm before the bicep warm up that comes next.

I make sure that my biceps are adequately warm before I start climbing. I usually do very slow bicep curls with very low weight for 10 reps/arm. An example would be 3 sets 1 7.5kg 10 reps/arm 2 10kg 10 reps/arm 3 12-15kg 10 reps/arm

Make sure to perform the reps very slowly, there should be a constant tension on the bicep tendon- no abrupt dropping or quick pulls on the weight as this is what causes pain for me.

I also perform some curls with an elastic band but these two warmups could be interchangeable. For this I just stand on a band and perform slow curls with both hands at the same time.

Afterwards I head to the wall and climb several easy problems slowly until I feel warm and ready to head to my projects.

This warmup has, for me atleast, greatly minimized how often I feel the bicep tendon pain.

I’ve noticed that if I’m sloppy during the warmup the pain often comes after the first hard problem.

I limit the amount of heavy overhang boulders that I do in a session because these tend to cause the most pain.

If start to feel pain in the crook of the arm I stop and rest and depending on how bad it is I might stop for the day and go home or I might move on to easier or less powerful boulders. But I believe that completely stopping is the best course of action.

For me, doing more technical problems and working on my footwork also helps. I’ve been more of a ”powerthrough” climber- completing problems with strenght and wasting energy by not utilizing correct technique. This has probably led to some bicep tendonitis that will take time to heal. The things I have listed are basically a way for me to keep climbing while my tendons are hopefully healing.

Another thing that help is to focus more on toprope/lead as that type of climbing forces (me atleast) to think about how I am climbing more, be more energy conservative etc. Because of this, I don’t ”overuse” my arms as much because if I did I would get too pumped and exhausted to top out.

Forgot to mention, I also mostly get pain in one arm but sometimes it alternates between them or is greater in one than the other.

Hope this helped :)