pain on my leftside radiates down the goin and leg

Hi. I have been suffering from pain on my leftside for roughly a yr and a half. Tje pain is almost were the left overy is but radiates down the goin and leg and round my back. The pain used tocome and go bt over the last 10 months roughly it has been constant.
Iv had several tests done:
An xray
An abdominal ultrasound
A transvaginal ultrasound
AnOther abdominal and pelvic ultrasound which also looked at the groin.

In the last ultrasound i explaine i had a lump in the pelvic area sort of in the groin which was painful the doctor said it was a lymph node but it was nothing to worry about.
Last week i had a full blood test an blood count which was normal.
My doctor doesnt seem to know what to do. The lump is painful but i dont know were the pain is exactly coming from. I also have constipation problems.

I just need help to find out what this could be because the pain is really getting to me.