From the symptoms given it sounds quite likely that you have a prolapse of one of the discs in the lumber region of the spine. Keep your self mobile and see what actually makes it feel worse, if it is bending and twisting then it is further indication of disc prolapse. Ibuprofen is none effective as it is an anti-inflammatory not a pain relief.
Make an appointment with a different Doc and take along a diary of what makes it worse or what gives you some relief. They will be reluctant to send you for further tests as the only way of getting a full diagnosis is an MRI scan, which are not cheap.
I have had three Ops on my lower spine so i know what you are going through, currently awaiting admission for a fourth op to have the lower four vertebra fused together and then plated and screwed, not bad for a forty year old!!