Can gastritis cause left side pain?

I've been experiencing pain in my left side for about 1.5 months.  The pain radiates from my ribs to my buttocks.  Yesterday my pain stayed in between my ribs and hip.  Occasionally, the pain will be between my ribs and hip on the right side.  I also have pain under my ribs in my abdominal area.  I had a pelvic and abdominal ultrasound and all came back ok, except I have a 2cm ovarian cyst.  I was told it is benign and shouldn't be causing me any pain.  I had an upper endoscopy done and was told I have some gastritis.  A biopsy was done and there is no infection.  Test just came back with having some inflammation.  I just started taking Nexium to relieve the gas and bloating.  That has helped the gas, but not my pain.  

I am at wits end with this pain.  I have had occasional bladder infections, but I have generally been a healthy person all my life.   Also, could a bladder infection be causing my pain?  I don't have the normal symptoms of a bladder infection.  I usually have frequent urination and back pain if I have bladder infection.  I do have problems with slow urine flow.

[yno]

yeah me too.. I'm 23 yrs old male.. I've been having this terrible lower left abdominal pain for 3weeks.. It all started when i got home from an out-of-town gig with my girlfriend. Then my tummy got suddenly upset.. Sometimes, not only the pelvic area is aching, but also my chest.. Also, i haven't taken any medicine/s yet.. There are several people here in the Internet haven't found any cure for this, that's why I have not yet give a doctor a visit since..