I feel pain in left side near stomach Sometimes the

Patient: I feel pain in left side near stomach. Sometimes the pain is very much unbearable but does not last for more than 4-5 seconds. I am suffering this for last 2-3- years but hardly paid attention. However i took medicines regularly for UTI but not for last 2 months. What can the be the reason?

Symptoms: Sudden unbearable pain lasting for 4-5 seconds