Pain after root canal and crown installed. Any suggestions?

had a root canal; then perm crown. Then crowned tooth began to act up. Hurts when tapped on side and pressured by tounge. Feel nervy sensation when gather saliva, suck in , move mouth. Nervy pain sometimes when chew(even when not chewing on that side). Pain seems to be at bottom of tooth area above the gum. Gums are not sore. Went back to dentist who said crown too high ; filed it down, removed some loose cement and gave antibiotics. That was 3 weeks ago. No change for better. need guidance- thx