She needs to see her Vet ASAP.....This could be a serious obstruction...Hopefully not, but you must get her in to see...Please let us know what you find out...Good luck, Karla
P.S. It's very possible that this is a disc/disk problem in her lower back...Will also give the same effects.....However, both are medically treated differently....
Both do create enormous pain!
GO TO THE VET NOW. It sounds like your dog has an intestinal blockage, which requires immediate attention. This is FATAL if not treated. - Blu
Agree with Karla and Blu, my first thought was a disc issue but constipation can be life threatening.
Yes, definitely need to be checked.