My 4 Year Old Cat Is An Excessive Licker. She

My 4 year old cat is an excessive licker. She is pulling her fur out in clumps. I've had her to two different vets and have had her skin analyzed and she has no fungus, etc. Both said that probably it is more than likely a physiological behavior. I would love to find something to help her. She's extremely hard to get her to take pills. Thank you!