Why am i getting these pains?

Im 18 year old Male im getting these sharp aches in my chest head arms and sometimes legs. they come and go real fast. sometimes theyre pretty intense and last a few seconds. dont know what it is. also my hands have been getting this weird numb feeling. i am a hypochondriac. i get a little scared everytime i feel something off. i dont know if these pains are stress related, i dont think they are because ive never had it like this before i did go to the hospital few days for nasty stomache ache everything came back normal so im guessing its nothing that wont show up in blood tests. could it be a blood clot somewhere or a pinched nerve or something?