What Causes Tightness In Throat While On Diet HCG Drops?

Today I started the Omni drops program(diet Hcg drops program) and I experiencing some throat tightness for about 2 hours now. I feel fine, but the throat tightness is very noticeable and never felt this. Do you think it is from this medicine or what could be some possible reasoning s? I m only allergic to sulfur that I know of.