Will Back Pain In The Pelvic Area Cause Problem To Diet?

Hi, I constantly feel nauseated, I have had a gastroscopy done last year due to a feeling of a lump in my throat and a feeling that I have a slick of grease that makes me fee sick sitting at the top of my oesophogus. I am on lansoprosil 250 daily after meals with dairy I still experiece bad acid, The neausea will not go away and I am now avoiding eating and have lost weight. Whether this is related i have constant lower back pain in the pelvic area. ANy thoughts?