Pains in lower left ribs, left stomach, migraines. No help with painkillers. What could it be?

Hi, I am a 15 year old female. I get pains in my lower left ribs which then go to my shoulder , I also get pains on my lower left stomach , I also get bad migrains quite a lot. I get sharp pains through other parts of my body but under the left rib and left lower stomach occur more and are more painful! The pain is much worse than and I haven t found any pain killers that will get rid of the pain. I am always feeling unwell, confused and lost. I have recently been doctors and hospitals due to a staph infection on my right leg, but I don t think that would have anything to do with the pains as I have been feeling like this and getting these pains for a year or two now. I haven t been able to find out what could be wrong with me and I just want to find out becasue I m so over feeling like this, I just want to feel normal again. I really hope you can tell me what could be wrong.