Hi welcome to health care magic.... You are having pain at navel region with tenderness.... So rule out colitis first.... Second possibility is of appendicitis if fever and vomitting associated.... USG abdomen helpful for it.... If fever is associated start antibiotic like ciprofloxacin for 5 days.... Take healthy and balanced diet... Junk foods , meat , excess spicy food restricted for few days.... Fruits more ... Take rest..... If pain occur in particular position or specific movement then it could be simple muscular pain... If still pain increasing and in USG no cause identifiable colonoscopy might needed. Take care.... Dr.Parth