X-ray show 3 gutta purcha on my upper molar.tip of one of gutta purcha had tiny, inflamation. will it work by grainding bit of crown to rest more?

Probably not: It's worth giving a bite adjustment a try, but chances are more likely that you will need to have that root canal retreated.

Root canal : Adjusting the bite can make chewing more comfortable. If there is infection, the therapy should be redone. It it is only inflammation, adjusting the bite will be adequate. Another x-ray should be taken in a year to see if there is any change in bone density.