I recently had some plumbing work done to my shower. Pipes replaced, faucet, as well as the hot/cold knobs. I went to take a shower a couple of days later. Water flowed fine through my shower head for about 5 seconds. And then it shut completely off. The water still ran from the faucet. Just not the shower head. I tried it again a few hours later. The same thing happens. What could be causing that?
Sounds like a little piece of crud flowed into the path of the water and blocked it. it's trapped in the hose/stem/pipe. as the hose/pipe drains, the crud slowly recedes, (it probably floats) waiting to spring forth with the next batch of water.
The fix? Remove + clean the head, and also run water though the empty pipe for a few moments to be sure (careful, it will shoot out fast).