anyone else get pain in your keyboarding arm? how do i avoid this???

i'm honestly not much of a gamer (especially on pc), but i've gotten really into ultrakill lately. my right hand using the mouse doesn't really hurt that bad, but my left arm/wrist/hand/fingers hurt like hell if i play for more than 20 minutes...is this normal? 😭😭 i'm playing on a laptop if that makes any difference. how the fuck do i avoid this because it hurts so bad, i'm not very used to pc gaming. is it an inevitable part of the ultrakill grind???