Crown left a big space between my molars and huge chunks of food get stuck in there which can only be removed with flossing. is there a fix for this?

Yes: Best thing to do is go back to the dentist thatmade the crown and have him remake it.

See your dentist: This is a problem that requires a face-to-face meeting with your doctor. In that meeting, your doctor will listen to you, perform a throrough examination and possibly order labs or other tests. Based on this information, he/she will be able to tell you what's wrong and what to do about it.