What can a palpable mass in the left lower quad be. with symptoms of severe pain at times that radiates to the lower back, and nite sweats at times.?

Mass/lump: A ct abdomen & pelvis is necessary to diagnose. Some possibilities are diverticular abscess or tumor.

See doctor ASAP: Without an exam it is hard to say. A complete physical, possibly blood work, and imaging (cat scan) would be helpful. A trip to the er might be helpful to determine what the mass is, and control your pain.

IBD: You may have inflammatory bowel disease like ulcerative colitis. Alternatively, it could just be irritable bowel disease. Do you have bloody diarrhea? You need to see a gastroenterologist or general surgeon. There are rare causes as well. You need a diagnosis.