History:

It likely grew naturally within specific groups, spreading as people moved. Wars, conquests, or slavery could have dramatically changed where this surname is found, as people were forced to relocate. Similarly, people might have chosen to move for jobs or religious reasons, taking this surname with them to new places.

Description:

I need more specialized resources to answer your question.

However, we can guess at some possibilities based on how surnames change over time. A shorter version might be Sham. Adding a letter, we might find Shammah. Or, a small vowel change could give us Shemm.