I been having pain in my lower right side abdominal what can it be?

Appendix vs. Muscle. Right lower abdominal pain always raises the issue of appendicitis. Usually it is tender and is accompanied by loss of appetite. But these are not hard and fast rules. When in doubt have a doctor put a hand on your stomach. You may have to come back at short intervals to be sure. It could be muscle strain, but better safe than sorry.