So, was having chest pain. holter was normal and ecg was normal. potassium was a little low . what next?

Work w/ your doctor: There are many possibilities with chest pain, and i'd recommend you involve your doctor in that evaluation. It sounds like you've already started a workup with him/her. Go back for a follow up, ask about the various next steps you might need for your problem.

Look for other cause: You need to look for some other cause of this chest pain, may not be the heart. Possibly, acid reflux or costochondritis/ inflammation of the rib cartilage or esophageal spasm.