Had root canal late march, gums still sore. went back to root canal doctor early june, he gave more antibiotic, still sore, to sore to get crown?

RCT soreness from?: I would not recommend having a crown made on a tooth until it is determined that the tooth has a good long term prognosis. We can't determine the cause of the soreness over the internet and therefore can't tell you whether or not to have the crown made. You should ask for a reasonable explanation as to the cause of the soreness, the long term prognosis & why any specific treatment is recommended.

Root canal pain: Wait until the tooth is pain free before you have the crown made. We can't diagnose the problem. The dentist who did the root canal should give you a reason for the prolonged pain. A second opinion can help,you get an answer. See an endodontist for this.