Just got x-ray for back pain and spine tenderness, notes were 'lumbarization' and 'mild facet hypertrophy'. could this explain the pain and tenderness?

Possibly: Those changes can certainly contribute to the pain.

Likely: Lumbarization is an X-ray finding indicating that the top of the sacrum actually appears t be part of the lumbar spine. This is a congenital defect that can limit mobility and cause chronic pain. Facet hypertrophy can be an indicator of excessive force/strain on that area of spine. Follow up with your doctor for further evaluation and treatment. Take Care!

Back pain: "Lumbarization" of the S1 vertebra means that it has not fused with S2, (racepinephrine) creating a point of motion within the sacrum and one or both sacro-iliac joints that usually does not exit, which can result in increased stress at S1-S2, (racepinephrine) and at the SI joints. Facet hypertrophy refers to proliferation of the bone about the facet joint, usually in response to stress. Both are known back pain generators.