FYI,
I have what sounds like the same type of pain and was diagnosed with a biceps sling injury.
Basically it usually involves a tear (major or minor) in the labrum and in the subscapularis. The long (I think) biceps tendons runs up and through a little groove at the top of the humerus and the subscap kind of holds it in place and the labrum keeps it tight. With both of those kind of loose from damage the biceps tendon tries to pop in and out of that groove (you can probably feel that happening when it does...at least I can).
The way they fix it is with a biceps tenodesis, which is where they sever the biceps tendon up by the labrum and then shorten it and screw it into the humerus itself.
As that scares me a bit, I'm going to try this peptide after I search out a decent distributor.
The longer the biceps tendon rubs/pops in and out the more wear it will get though and eventually it could burst. The way my orthosurgeon described it, imagine one of the ropes tying down a boat at the dock. Over time, as it slides back and forth over the edge of the dock it will fray and eventually rip completely.
Glad to hear the peptide seems to have helped you. Hopefully I'll get similar results.
The Mayor