I am a 30 year old African American, and for as long as I can remember I have had this itchy black head like bumps all over my leg. Sometimes when it gets caught in fabric it really stings. Sometimes it looks like its fading but it doesn't. It just looks like a stocking of bumps on my leg and now I have noticed its starting to spread to my arms. Any help in identifying what this is would be helpful.

This sounds like something other than black heads... they usually don't "spread"! Seems like your hair follicles are highly infected... you should consult with a doctor/dermatologist. Sounds like you need prescription grade products.