Hey sounds like you have the same issue as me...
You must get an xray or scan to determine whats wrong and dont sit down lay down thats what I have to do...
take care
Physical therapy did wonders for me. I had similar pains and found out that I had a bulged disc. I was about 25 at the time.
The firstb thing you need is an evaluation by an M.D. at the earliest opportunity.
You have symptoms consistant with compression of the sciatic nerve. An MRI of the lumbar region is indicated for a definitive diagnosis. An x-ray is insufficient. Often the condition is self-limiting disappears by itself.
Don't despair. After rest, physical therapy and some anti-inflammatories, the symptoms often resolve.