don't worry to much! Spasm situation are painful and disabling but most or the time are just a sign that we havn't looked after the core well enough. You will need a MRI to confirm any disc problem we can then rule out disc instability (if you don't have leg symptoms this is unlikely)

Can I ask why have u seen two physios and was the only treatment in exercise form? I would say you will need around ten manual therapy session at a reasonably high frequency to get you any better. This should include passive stretching, mobilisation, massage to get this condition under control. It might be best to go private where you should find you are given more hands on treatment.

P.s - like I said before I would seek
Manipulation from a osteopath or a chiropractor (a chiropractor can take x-rays and check for any signs of disc degeneration). Most of the complaints these professions see are from the back so you would be in good hands.