Tingling Sensation of Unknown Origin

While I was hoping to cross off symptoms as I progressed through the rounds, a new one appeared: parasthesia. What is parasthesia? From The American Heritage® Medical Dictionary:

par·es·the·sia or par·aes·the·sia (păr′ĭs-thē′zhə) noun A skin sensation, such as burning, prickling, itching, or tingling, with no apparent physical cause.

Without schedule or known reason, I get the sensation of my skin tingling on the right-side of my chest. It’s only a small section of my skin—maybe a three-inch diameter—that suddenly, and without warning starts to tingle. The duration is less than five-minutes and the experience is not unpleasant.

This new symptom first appeared around the same time I increased my daily Milk Thistle dosage from 250 mg to 750 mg. Considering the tingling sensation is located in the same place that my liver exists—excluding the fact that my ribcage lies between it—I have to wonder if they are associated.