Thank you for the query.
Joint pains and bowels problems like mucus in the stool, constipation, cramping, etc. can be caused by inflammatory bowels disease (Crohns disease or Ulcerative Colitis
Lower left abdominal pain
is quite characteristic for diverticulitis
of the sigmoid colon. This disease is caused by chronic constipation
. Due to increased pressure in the large intestine, the wall gets weaker and some kind of pouches appear (diverticles). If the stool stuck in such pouch, an inflammation appears.
I suggest you to do not wait anymore and visit your doctor. Colonoscopy should be done.
Hope this will help.