back pain vs flank pain?

How can one distinguish the difference?
I wasn't sure which dr.to go to, but now that I've read the posts, it's best to go to my primary care dr.
I've never ever had back problems. As a matter of fact I've counted myself very lucky compared to others with such night mare stories.
I've had this annoying,vague dull aching deep inside my back on the right side. I don't know if its the spine itself, or if it's a knotted muscle( due to alot of stress)or is it flank pain. what is flank pain? I thought that was where the hip is.
I wake up with it and go to bed with it. Sleeping on my right side only aggrivates it further.
We discovered by chance a few yrs.ago through a fall my mother had taken which broke her hip, that she has a bone disease, not arthritis like we thought. her bone surgeon came out and really lit into the children that this is serious. It wasn't our fault though,we could never get her to go to the dr. I remember when she was able to walk with a straight spine when I was alittle girl, and then during my teens, all my freinds would ask why my mother was bent over and her knees bent in. her toes and feet were grotesquely bent. It even looked painful. she used to whince when she'd get stabbing pains. she never went for help. At the time of the SX they also determined her knee cap totally disintergrated.
I tryed to convince her to get surgery done but she said she was too old of a woman. she was only in her late 70's at the time. she just passed away this last Dec.03 at the age of 83.