Please need help with mortgage loan stuff?

Me and my husband got pre-approved so we are now looking at houses. We went through WellsFargo about teo months ago and the lender approved us for an ARM. My realtor has her own lender and we are thinking about going with her lender instead so she can get us pre-approved for a fixed rate loan. What I am worried about it that I heard it can hurt your credit score if you have it checked/ran to many times it can hurt your score, is this true? I dont know what to do, in this situation should I just go with my realtors lender or try to work with the lender through wellsfargo and avoid having my credit ran again and having it possibly hurt our credit scores.