I would advise you to seek refferal to an Osteopath, which is an increacingly availble via the nhs and GP refferal - or even reffer yourself to a private practitioner, in which case you would have to pay but could be seen tomorrow; postural problems such as those you discribe are an osteopaths area of experteise, though many physiotherapists are highly compitent in the area.

Your eargerness to be proactive is very good, but without being assesed clinicians are not going to be able to offer proper advice to you but rather give you a list of differentials.

I notice you mentioned a previous back injury so would suggest you read up on or at least ask your practitioner about arthrogenic inhibition; It is a relativly common cause of dysfunction that follows on from injurys and predispose to further problems in the future, the assosiation of Pilates to aiding back pain is due to its effectiveness in countering this. But again I'm offering a differential...

J