I'm 18, heart rate used to be good in the 60-80 range at rest. now that i'm on norvasc (amlodipine) 5 mg, it's 90-120 range at rest. is it even safe to exercise?!

Heart rate: Norvasc (amlodipine) doesn't tend to elevated heart rate. I wonder if there is something else going on. 90-100 would still be considered normal. 100-120 doesn't need to be treated if it is normal sinus rhythm and well tolerated. You will need to have an ECG done at least to make sure there's no abnormal rhythm. After investigation, you may be cleared to exercise.