Can a lumbar facet radio frequency ablation cause GI motility problem?

I only had laser frequency on mid back, and this seemed to help with exercises recommended by a chiropractor. My lower back pain is pretty much untreated; one gets to accept the pain, become accustomed to to it. The best advice that was given to me was to not get overweight: no abdominal bulge.

The nerves of the lumbar spine control the lower digestive tract--the large intestine and anus. Theoretically, the answer is yes. Nerves, other than the medial branch, can be damaged or numbed during this procedure. It is more likely that the pressure originally causing pain is pressuring the nerves controlling the lower portion of the digestive tract.
The target medial branch nerve only carries pain signals, but the other nerves are bunched together and may have been affected marginally.
Do you know the reason the pain nerve was being pinched ( spondylosis, disc buldge, vertebral height reduction)?
You may be less active, taking too much calcium, not enough magnesium, not enough fluid. Constipation itself can cause a loss of feeling in the lower intestine. I suggest seeing a chiropractor if your bones aren't compromised.

Are you on prescribed medication that could be contributing to this?

Most likely a result of anesthesia more than nerve damage. Fluids for constipation are important and necessary. If you’re on narcotic pain meds they too can cause slowed motility in the gut.