I had a car accident a little more than 2 months back.
I had an L2 compression fracture in one vertebra in my lower back.
I saw an orthopaedic who gave me general pain medication and asked me to carry on the normal activities as usual. He DID not suggest bed rest.
I recovered quite well.
Just about a week back, a got a bad jolt in the car I was travelling.

I did not feel any specific pain at that time.
However, after that I have started feeling a nagging, itchy pain almost in the same area as I had my fracture before.
My orthopaedic again gave me some pain medication and asked me to join physiotherapy.

My question is why this sudden pain out of the blue? Would I be hurting myself if I go for Physiotherapy? Have I sustained a new fracture? Would the orthopaedic get to know if my fracture is the old one from the X-Ray? PS: He never consulted the old X-Ray report this time.

Generally speaking, absolute bed rest of 6 weeks or more is required fro compression fractures of vertebra where there is no neurodeficit i.e. no weakness in the limbs along with analgesics & anti-inflammatory medications. A review is suggested after 6 weeks or earlier if necessary. If the pain has completely subsided, the patient is advised physiotherapy to reduce the muscle stiffness which a result of clotted blood & prolonged bed rest. If the pain is present to any degree, the rest is extended for 2 weeks more & a repeat x ray is done to confirm fracture healing followed by physiotherapy.
If there is a repeat injury to back, it is best to x ray the part & decide the treatment accordingly.

It sounds like the compression on a nerve which is the ichy pain, and which is why you were sent to physio - and perhaps consider chiropractic care - to reduce the tension and tightness and take pressure off the nerve. Wher there was an already existing injury in recovery it is normal that your muscles in a sudden jolt would tighten and not let go around the injury inorder to protect your spine. Your body is programmed to surviive :)