I have intermittent shooting pain to the left of the base of my left thumb nail. relieved by strong pressure. what might be the cause? what treatment?

Tenosynovitis? : An examination by a doctor should probably give you a good idea of what it is that's bothering you and suggest the best treatment.

?digital nerve : Perhaps you injured a terminal branch of a digital nerve, and this painful neuralgia is controllable from your maneuver, but might wonder about a localized nailbed infection if this is indeed recent (a felon?). Have your doctor check this out.