My 1.5 year old pug recently started to chase her tail/try to bite it and whine. During the day she'll do it no more than twice and it is very brief but when it is bedtime, she will chase her tail/try to bite it and whine for about 5 minutes before settling down to sleep. I don't think it's something in her tail because she lets me stroke it and doesn't appear to be in pain. I thought it might be an anal gland issue so I had them expressed but she still cries every night. She is eating and behaving normally. She is my first dog so I am unsure of what this could mean. Is this a health issue or behavioral? I don't know if it is related but I also noticed that a week ago she was licking everything (couches, her bed, my clothes). she stopped a few days later. Today I noticed she was licking/nibbling on her back paw so now I am thinking it is allergies and she chases her tail because she's itchy?