When to the doctor they said i have inner ear infection (otitis media) they gave me amox- calv took all the meds 3 weeks later my ears still hurt? why do they still hurt?

Several options: A middle ear infection generally hurts because the mass of germs/pus/fluid in the tiny middle ear space pushes the drum out. When/if the germs die the mass begins to shrink & should resolve with fluid draining into the throat through the Eustachian tube. That can suck the drum in, causing some transient pain. The infection could also return after meds stop.Seek a re-check.