I have a terrible pain in my right lower abdomen what could this be?

Many things. Pain in the right lower abdomen can be many things. It can be appendicitis, kidney stones, gas, urinary tract infection or muscular strain among many, many others. If you are a female, there are some gynecologic conditions that can cause pain in that area. If the pain is intense, prolonged or recurrent or associated with other symptoms like fever and vomiting, i would urge you to be evaluated.