Red Lawhern
Your use of the term "flashing" with respect to your head seems a bit imprecise. If you mean distinct "flashes" of electric-shock type pain, then you could be dealing with some variant of trigeminal neuralgia (tic deloreaux). However, your report of generalized weakness concerns me: please see a physician immediately for evaluation of possible stroke or TIA (transient eschemic attack - mini-stroke), or siezure related disorders.