Could it be arthritis..?

Okay, i am 13. and whenever it is going to rain, or is raining, or precipitating, lol, my knee and ankle hurt like crazyyyy! and also just sometimes when im trying to sleep it doesnt have to be raining. but anyways. it hurts like soooo bad. and i'm wondering if it could be arthritis? my mom has arthritis really bad in the sameee knee. what can i do to stop the pain until i get to a doctor also? or will they give me meds for it or will i just take otc stuff? if it's even arthritis of course. just wondering! thanks, and nooooo mean/hateful answers please! (: