I have started to use bcaa's in powder form during my workouts. are there any side effects? i am getting some joint pain and really bad constipation

Proper fluid intake: Bcaa are isolated Amino Acids and they can cause constipation. Watch fluids especially around training sessions. You need to take in extra fluids since the aa's tend to harden the stool. I haven't heard of their causing joint pain. Try adding omega fish oils to see if this eases the joint problem. Also try lifting lighter for a while.