My muscles keep on...................?

Today I was strecting and which ever muscle i was working on. It would twich inside. After a bit of rest I was standing and those muscle were twiching/moving inside. (like when you feel your heart pulse, but it wasnt that). When I put pressure on my leg or arm, the twitching will start again. (its like when you sit, only with your toe touching the ground, the leg starts moving) that was happening to me. It also happens randomly even when im not doing anything.
Can anyone tell me what this is, and why it occurs?My muscles keep on...................?
Your nerves. Possibly your mighty muscles have piched nerves.
Maybe you pusheda little too hard. Theres what your mind thinks you can do, but the reality is that there is only so much your body can take.
Your muscles are twitching because you are stressed. Both physical and mental stress can cause this. When I a stressed the muscle right below my left eye tends to twitch. It's annoying, I know, but it's part of life.
for the most part its harmless. twitching can sometimes be caused by a build up of lactic acid. improved circulation or even a hot shower can help.