Certainly when there is some biceps brachii tendinosis and or bicipitoradial bursitis / effusion it can impinge on the median nerve as it is very close .
Given the pain correlating to supination and pronation I would also consider the spectrum of biceps brachii impingement.
Some people have a tight space between their radial tuberosity (where the biceps brachii inserts) and the ulna so when they supinate and pronate they get impingement. If they supinate and pronate a lot they get compression tendinopathy of the biceps brachii and may even rupture it with minimal force. I have seen it in table tennis players several times due to the repetitive and rapid supination and pronation.
There is a case of the week presentation on the topic. Please review it and see what you think.
So yes, I think you are on the right track, but I would also ask more questions of the biceps brachii tendons.
You can use the pronator tires window, the cobra technique and the cotton reel technique to assess the tendon and look for impingement.
Short axis in the pronator terms technique is great to observe the tendon path during supination and pronation, the cobra technique also works for this,
Nice one,
Steve