I am new to sculpting and I am having a mesh here which I decided to make bigger to create sort of a body out of it, so I locked the upper part of the mesh with B and used the standard brush to extrude the mesh down and now, as seen in the picture the mesh is pretty stretched at one part and not usable for further sculpting.
I'd appreciate if somebody could tell me how to avoid or fix this.
Thanks a lot for the attention and help.