I'm having the same problem with our oldest Bichon at the moment. Tonight he is really uncomfy and keeps rubbing his bottom on the floor. He has been doing this for a few days now and we had him to the vets a week or so ago and had his anal glands emptied by a nurse but I don't think she did them properly and so last Tuesday night we saw our vet and he emptied them and gave him an injection to settle things down. He's still doing it though so haven't a clue what is wrong. He was wormed a couple of days ago so it can't be worms. He just can't settle at all.