What Causes Pain From Navel To Appendix Area And Lower Abdominal Area?

I have SLE and APs. 5 weeks ago i developed a bad back problem or so I thought. After a few days the pain went to my navel and spread over to my appendix area. Since then I cannot eat properly as within 20 mins of eating I have to go to the loo and have terrible abdominal pain. I have been to the docs. and the first dr. said he wanted to rule out ibs. He thought I had something significant related to the lupus but wouldnt tell me what. He insisted I go to the doctors the following day and arrange an ultrasound. Since then I have seen 4 doctors. The last one finally said I needed an ultrasound but now 10 days later I still do not have an appointment. I cannot sit but can stand or lay down as whatever it is seems to be pressing on my back when I sit down. Sometimes a lump appears and can swell to 4 ins outside my body. Im getting quite worried