Go ahead and try it, just monitor the sensitivity... if it starts looking red and irritated and feeling more raw than normal, then ease back. Chest skin is usually tougher than the face so probably shouldn't hurt too much.
I get them in the same area and it's like the T zone of my chest, the pores are dilated and there is a super micro comedone/blackhead in almost every little pore. Scrubbing and neutrogena body wash doesn't really do anything for me. I even tried some of the skin solutions 20% salicylic acid gel and it barely makes a difference because none of that can seem to keep up with the constant sebum production of my messed up body. It just pumps is out continuously.