just did a back workout and my first heavy work set on lat pull downs i felt a pop/and jolt inside my bicep. It felt more like in the mid/upper part so not the typical distal.  Cut the workout and went home. 
a week before this I felt something in the same bicep in my bicep barbel curls so where I cut that workout short also. I kind of forgot about it and went ahead and did this back workout stupidly. 
There is no visible change. No bruising. No swelling so far.
So when these pops/jolts occurs can it be muscle fiber tear within the muscle? I suspect this. Or a tendon strain. It felt like a hard pop and jolted the arm kind of.
Anyways i will hold myself to rest completely from biceps and back work for a month now and slowly start back with light weights after to see how it feels. I really don't want another bad tear...