What are these white scabs on my head?

Everysince ive been sleeping with was my bf but now my hubby ever now and ill have these white kinda like scabs that i have to scratch to get out and on the the head to feels like a sore but when i pull it out its white flakes and its only on one part of my head ,for a while its been on my left side but now its its been on my back of my hair about a month,when i pulled them out theyll be gone for a couple days and then ill do the same thing.itll be doing this for about a month and then itll be gone for awhile but they always come back.i want to no what they are and nad how to keep them gone