The tip of my left index finger will start to throb unexpectedly. some times it's in a different finger, and lately i've noticed it in my big toe as well.

Finger pain: Throbbing pain of the finger tips can be due to vascular problems (worse in cold weather), Raynaud's syndrome, associated with coolness to the touch and pale color, hypothyroidism, transient spasming of the digital arteries, peripheral neuropathy, sickle cell anemia (African American), arthritis, carpal tunnel syndrome to name a few. All of these can be worked up by your PCP, usually with labs