I have pain on my left lower rib it comes and goes what could cause that may hurt for days and quit for days at a time thank you

Are you sure ribs?: If you truly have rib pain, ie, you have pain when you press on the rib cage, it is almost certainly a muscle/skeletal issue. If you don't have actual pain on the rib it may actually be pain in your abdomen-look at a drawing of the abdomen and note the diaphragm, which separates the chest and abdominal cavity, actually rises above the bottom of the ribs. Go see your doctor, it could be serious!

Rib pain: This is most likely costchondritis. There are a variety of causes including viral or traumatic (i.e. Blunt force or coughing) etiologies.