With a very bright light source in the frame some lenses will always flare. Make sure your lens is clean (rear element too). Those spots are where the light sources are reflecting off glass surfaces in the lens, so less complicated lenses sometimes work better. Super zooms are very complicated. Regular zooms less so. Primes should give you the least trouble of all, but they flare too. Remove any filters. Fancier multi-coatings may help some so higher quality lenses are supposed to flare less, although my most expensive lenses are more flare prone than normal IMO.