Hello Dear I evaluated your query in depth . # Sudden insidious onset of triceps pain is usually muscular sprain / strain related to certain un noticed insult on ligaments / tendons / nerve endings in most cases . # Head ache may or may not be in relation with this . # I recommend you certain steps to follow at home as - apply alternate ice & lukewarm water to upper arm every 3 hourly . - local analgesic spray 6 hourly - avoid pressure over that arm while sleeping / resting , avoid weight bearing / work outs till total recovery - analgesic tablets 3 times a day after meals - light exercises at home not vigorous ones - maintain hydration with plenty of liquids , keep BP , Blood sugar in control - avoid smoking / alcohol / any abuse substances if using - if after 24 hours , pain score decrease continue this for next 4-5 days, if persistent in same intensity , consult your doctor . Hope this will help you definitely to some extent . Feel free to ask any further health related issues in future anytime . Thanks for using Health care magic . Regards .