Q. My dog is constantly scratching and chewing at herself she has no fleas is there anything I can do to help
A. It would be best to pin point the cause of scratching. If she doesn't have fleas then it could be allergies (food/environmental). It would be best to discuss this with your vet who can rule out any other possible causes.
I would also recommend switching food to a high quality grain free food with a different protein than what she currently eats (chicken to fish) and see if there is any improvement after several weeks.
Without knowing the cause of the scratching it is hard to correct the problem and provide long term relief.