twitching in left biceps

[Hydrofied4]

I've been getting this twitch in my left bicep during my workout. It's an uneasy feeling, like I'm about to pull a muscle or something. This usually happens during flies or pull-downs. Afterwards, my left arm feels very tense, and my bicep has a bit of discomfort. Well nothing has happened yet, but I'm concern I might injure myself and not be able to workout. Is this due to my left arm being weaker than my right?

[hou059]

Hey, do you stretch at all before lifting? That might help you out.

[Gooseneck]

I get a muscle twitch and jumping feeling sometimes when I do tricep pressdowns. I just stretch it out and watch what I'm doing and everything is gravy.