Suggest Treatment For Cold Sore On Lips With Fibromyalgia

I had shingles at the age of 19. I'm 40 now. I also have Fibromyalgia & hypothyroidism which is being treated. I exercise when I can (walking, yoga, stretching) for the Fibro, but when I push myself...running hard or swimming...I find that I get usually one cold sore on my lip...& I feel like crud for about a week afterward. Is it not a good idea to do strenuous exercise because of the shingles? Thanks!