What Are The Pores With Whitish Crusty Nodules In My Shoulder?

Hello, I have developed a skin condition on my upper back, and shoulders. My daughter looked at it and she tells me that it looks like the pores are developing/secreting very small whitish crusty nodules. The texture of the skin to the touch is bumpy. If I scratch my back with my fingernails some of those nodules will dislodge, there is no pain associated with these "bumps", however this has gone o for quite some time now, perhaps a year or more.

The cores that dislodge are very small, hard and whitish.

Thanks in advance!
Warren