There is a slight pain in lower abdomen on the right hand side at the naval level. what could be the cause for the pain?

Could be lots: Including gas, hernia, ureteral stone, colon issue and even early appendicitis (a surgical urgency/emergency). Females also have gyn possibilities. Can't tell here. Any symptoms like nausea, fever, loss of appetite, vomiting, change in bowels-diarrhea, constipation, urge but no bm, back pain, smelly or discolored urine, er asap. Doesn't resolve?-md asap or er.