Son hangs on my chest literally every 5-10 minutes. Or I'll lie down a…

Son hangs on my chest literally every 5-10 minutes. Or I'll lie down anywhere, for him it's a signal and he runs to get me to give him a breastfeed. I've been eating normal food lately, but in priority is breastfeeding ? He has gotten so dirty on my breasts that my nipples hurt terribly. What should I do? Teach him? But he's still so little, he was less than 10 days old yesterday.