More likely strain to the ql muscle with lumbar facet irritation very common in recriational golfers.
Use facet provocative testing to first rule this out positive kemps with no leg pain will do.
Also palpating flank deep is very important to establish ql muscle irritation.
Ask patient to describe pain when bending laterally ask for differences in character and location. Bending away irrites muscle bending towards irritates facet joints.
Flexion requires ql muscle to fire in stabilisation action leading to pain.
Does that help?