1 Angina Pectoris: It is described as a pain located at the back of the breast bone which may be sharp or dull. This sensation may radiate or crawl to the hand, arm, left shoulder, or jaw.  Vasculitis: When the small to medium sized arteries are inflamed, head tingling and numbness may result.
Most species of shark eat things like fish, crustaceans, mollusks, plankton, krill, marine mammals and other sharks. Sharks also have a very acute sense of smell that allows them to detect blood in the water from miles away.
A few things that could attract a shark to a human is blood (which can also cause a feeding frenzy) and a human paddling out to catch some waves (surfing) looks like a seal so that can also attract sharks, however sharks have a keen sense of smell so it is more likely that blood will attract sharks.