Why My Armpit Hairs Are Not Grown Fully In 25 Years?

hi my name's Jan-Ove Tor, i am 25 and havn't fully grown armpit hair yet. I mean i always had a small hair since i was 21 but it hasn't grown any bigger. is that a health issue?
One more thing, when i sit for a long time and then stretch. i get dizzy and and sometimes become unconciious for some seconds, what problems do i have?