What Causes Pain In Wrist And Elbow?

Im 18 and i have constant pain in my wrist and just recently my elbow. My wrist pops easily. Experience less pain when moving my wrist or stretching my fingers and wrist. Lots of stress in my forearm. I lift weights almost every day and have a bad practice of bending my wrist all the way back when doing so. The aching is only in my left wrist and left elbow.