Hi
Clinical Sports Med (Brukner and Kahn) is good for soft tissue acute injuries
I used Magee's Orthopaedic physical Assessment when i was in your shoes which is good for assessment but left me still asking "now what" - perhaps it has treatment in it now.
Florence Kendall's muscles book is good for muscles and possible exercises
Perhaps you could use some clinical reasoning and ask yourself the following questions:
1. What are all the myofascial (that is muscles and fascial and soft tissue structures) that could be related to this problem
2. What are the articular structures (bone, joint surface, cartilage, ligaments, capsule etc) that could be part of the problem
3. What are the neural aspects (nerve, motor control, CNS/ANS/PNS, etc) that could be involved
4. What are any visceral aspects that could be involved (obviously vital organs, the soft tissue around them (like omentum), lymphatics, arteries, veins, etc)
5. Are there any pyschosocial behaviours (yellow flags)
6. What are their coping strategies like - adaptive (moves away from the pain) or maladaptive (extension of L/S causes pain but has increased lordosis - that is, moves into painful region).
Good luck! If you ask yourself those questions constantly throughout your career and try to expand the possible suspects (be specific), you will become a great physio because you will always be learning!!