Have been gassy & bloated after eating dinner & before had intermittent cramping on right side w/lower back pain. not getting worse. appendicitis?

Can't tell: There are several things that can cause the described symptoms. A critical component of the history is the length of time and pattern of the pain. The physical exam is also very important and some labs and X-ray studies may help. It can be difficult for a doctor to differentiate the causes. Delay in diagnosis can cause complications, so see a doctor soon if you're worried about appendicitis.

Gallbladder disease: is probably is what you have and not appendicitis. You probably need some tests such as ultrasound of gallbladder, gallbladder scan , blood and urine tests for gallbladder diseases. See your doctor.