I'm having trouble sculpting... Help?

I am curently in the process of sculpting arms for a figure of mine… but i cant figure out how to get past the shoulder muscle via adding clay, or extruding/grab without losing TONS of detail… Any hints?

are you using the sculpting brush on a high poly base, or modelling by extrusion? If you are using multi res and the sculpting brush, make sure the base is a little more dense in polys to begin with, in the area that needs more detail. if you are modelling by extrusion, a wireframe render would help.