I just recently went on to adderal. I'm taking two 10 mg tablets each day for school and one 10 mg on weekends. I recently started to have a pain in my left arm. It feels like it's just a muscle pull, cause I went to the gym for the first time this was on Tuesday the 7th in a few weeks and did shoulder shrugs at a weight I wasn't used too. And before that I never noticed anything with my arm, and it's been hurting since. So do you think its from the medicine or just the gym workout. I'm also 16 so it might be growing pains.