Back pain

Patient: Hello, I have had some lower back pain on the left it is right where my left cheek begins…I also have some pain in the crease of my leg and pelvic area..it comes and goes and is worse when bending and sitting . If I put my chin to my chest it pulls and hurts my back as well. Could this be something serious or does it sound benign

Symptoms: Back pain….some left pelvic pain , mild

Doctor: