The crown too low and gums receding, what's the solution?

After my 30th largest molar is crowned, I felt the crown too high and went back to the dentist to ground it lower, then the opposite tooth 3’s crown gum recede, can see the dark line of the crown, it’s getting wider. Now I often grind my teeth, the pressure of the grinding is on the 31 resulting in chipping on surface adjacent to 32,it’s getting larger and deeper, painful when flushing with water floss. 30th crown’s gum is also recede. Why problems happen? Please advice me the treatments. Thanks