My granddaughter had two attempts today for a spinal tap. Was unable to get fluid both times. Tonight is in a lot of back pain. Is this normal?

Back pain. Likely the back pain is from the tap procedure and in most case this resolves over a day or two. If the pain last longer than 3-4 days then i would contact the doctor that did the tap.
Yes. It is normal to have some pain after a spinal tap. I would expect the pain to eventually resolve 100% - the time frame is different for each individual, but most patients will be better within a few days. Try ice and anti-inflammatories. See a physician if significant pain persists for greater than 10 - 14 days.