Crowned, root canalled through crown. Sensitive 8 months so far. Rd.-ray show, one of tip of gutta p. show bit inflamed. By grinding crown, will it ok?

Maybe. Usually root canal pain resolves within a few days. Keep in touch with your dentist and consider talking with your dentist about options such as re-treatment, a retro-fill filling, or removal.
May indicate problem. It is not normal to have sensitivity 8 months following rct. It may indicate a failed rct, fracture on root which may or may show on conventional x-ray, unfilled accessory canal, or perhaps a result of bruxism or still uneven bite. If this can't be resolved completely within a few days after bite adjustment, you might want to consult with another endodontist and take a cbct scan (3d image).
Pain. Grinding on the crown is usually done if the occlusion is the source of the pain. If it is a problem with the root, this will not help.
Second opinion. I recommend you have a second opinion by a microscopically trained endodontist. At this point your tooth should be comfortable.