There are several things we need to work on to avoid lower back pain like:
1. Avoid smoking / Drinking alcohol
2. Wearing high heels
3. Prolong sitting
4. Keep check your body weight
5. Lifting heavy weights or any objects in inappropriate way
These are fewer things we should keep in mind to avoid back pain.
Prevention
1. Core strengthening exercise with pelvic floor
2. Proper diet in a right way
3. Sleep sideways
4. Reduce stress
5.Maintain proper posture
Assessment and diagnosis
There are several ways to diagnosis of back pain:
1. Physical examination
2. X-Ray
3. MRI etc
Physiotherapy treatment
Physiotherapy can treat back pain by electrotherapy or by any other mean like Manual Therapy, Chiropractic, Acupuncture and Dry/wet fire cupping.