What excercises can you do to help lower back pain?

First get examined: before becoming your own physical therapist. I suggest a PT consultation and working with a trainer at the gym. Slow, passive stretching: flexion, extension, internal and external rotation. This should be done with direct observation and direction by a trained physical therapist and/or personal trainer. Use resistance bands and avoid heavy weight lifting. Look into basic beginner yoga or pilates.

Back pain: This source of information should help. https://familydoctor.org/condition/low-back-pain/