I think i've messed my arms up lifting weights. it's always in pain i don't know what's wrong?

Strained muscles are: The most common cause of this problem due to doing too much, too soon. If you try lifting too heavy weights or too frequently, when the body is not conditioned properly, you'll hurt yourself. Pace down and decrease the weights to restart a couple of notches below the time you hurt yourself . Once the symptoms improve then slowly and gradually increase the weights and frequency.