Anyone else have these symptoms?

My sister has been having in her left pain for several weeks.  She describes it as a deep pain in her side that is a dull constant ache.  The pain radiates to both the front and back.  Also her skin is sensitive on the side over top where the pain is.  She said the pain actually feels better when she is laying on the side the pain is on when she's in bed. The pain gets worse as the day goes on.  Also, when she wakes up from a nap, the pain is worse but not after waking up in the morning. She is in pain whether sitting or laying but sometimes will lessen when she changes position.  Applying heat will also lessen the pain.  She had a CT scan of the abdomen, which was normal.  She also had an x-ray of the spine, which was normal for someone 48 years of age.  Does anyone have any suggestions as to what the pain may be, or even what specialty she should go to for further evaluation?  Thanks for your input.