My weights jumped up on my last cycle (including Tren) and I was lifting heavier than ever. By the end, one of my both my shoulders were hurting and I have what I assume is tennis elbow in my right arm. Totally anecdotal, but I think I pushed too hard, too often when I saw my weights jump.

Clarky above is right that low E2 can cause joint pain. In my case I found out my E2 was over 300, sooooo that wasn't a problem for me.