Dog has anal pain and tail is shaking.

[Klaraj7]

My dog is seven months old. She has a very bad fishy smell from her anal. Her tail also shakes constantly.
She can move it and it is not limp. But when I touch her around that area she jumps. She is also very constipated. We went to the doctors and they said her left anal gland was full. After they cleaned it she was able to go number two a little bit better. Then it became even worse. Her anal is also sticking out and hard.
I am also wondering if she has a digestion issue. Her stomach is very sensitive and she throws up every time she eats. She is allergic to chicken. So we are having a hard time finding something natural without chicken.

[Margot49]

I suggest you take her back to your Vet for a thorough exam as she might well have an anal gland infection.  Her anal is sticking out? You mean something is sticking out of her rectum?  If that is the case, she may have a prolapse and that needs to be addressed!  If she is constipated, that could be the cause.  What did your Vet say about her vomiting after her meals as that is not normal?  Maybe try a fish based food with no grains.  You can also add some canned pumpkin (not the pie filling) to her food which might help with the constipation.
If you have mentioned all this to your Vet and he/she is not addressing these issues, I suggest you find another Vet for a second opinion.