I had the ablation about 6 months ago and had very good results with it. I had both sides of the facet joints done but the doc told me the protocol was that they can't do both sides on the same day so I had about 3 weeks in-between treatments. I can't imagine why your doc said he could only do one side for you - there really isn't a downside to the treatment. Worst case, even if the treatment doesn't give you relief, the nerves will just regenerate 6-12 months later and no problems.
I think I will call the doc and see about doing another session with the ablation since I am starting to get some of the earlier pain issues due to back pain coming back (foot nurabness, leg pain, shooting pains up my leg into my back). Even if I get only 6 months of relief, I'll be happy to go through the procedure each time. I'd say the treatment took me from a 7-8 on the pain scale down to a 2 for most of the time with the occasional bad day here and there.
I don't think the RF treatment was really any worse than the normal injections as far as pain goes. They do nurab it a little but you still need to be able to feel part of the procedure to tell the doc where/what you are feeling.
I would say I was a little more sore after the RF treatment than the normal injections and the drive home wasn't the greatest but I just went home and got the ice pack and a pain pill and went to bed. The next day was still a little sore but certainly managable and went to work with no problems.
Good luck,
Alan.