pain during heat?

Question
I have a 3 1/2 year old Chi.
She has never had puppies. She has been with a male dog before, but he was fixed. That was during her last heat.
He is no longer living here. [[I foster dogs]]
She has just came back into heat.
She has always been mood during her heat. This time though she seems uncomfortable when trying to lie down.
She circles trying to find a comfortable position to lay down. She will lay for a minute and she will raise her rear in the air for a while.
She doesn't do this all the time.
It is like she has "cramps" like a human would.

I never had a dog do this before.

have you ever heard of anything like this?
What could cause it?

thanks!  

Answer
Crystal,
I highly reccomend having your dog spayed. It is an affordable procedure that is not at all hard on your dog (they almost always go home that day and resume normal activity the very next day). There are a lot of problems that can arise in the reproductive systems of unspayed female dogs, and she needs to be examined to determine what it is. If you aren't planning on breeding her (and I wouldn't reccomend it anyway if she's having this type of problem), spaying is definately something that would be beneficial to her health.
It is possible that she is experiencing cramps, but it could be any number of other things, like a pyometra- a serious condition that can arise in unspayed females.
Your dog needs to be examined by a veterinarian.
Thanks for your question and good luck!
Ashley