I'm not sure when it started, but I noticed Wed night for sure that Maggie was not her playful self and was acting "off." I put it down to depression from the torrential rain we had all day. At one point she had gone into her crate which is very odd unless there is construction or a party going on.
This morning (Thurs morning) she was very subdued, she seemed sleepy. She laid with my son in his bed and didn't even bounce out of there when she heard son2 come out of his room. Someone rang the doorbell and she came down and gave them 1/4 of the normal greeting and then just sort of stood there, shaking a little. Not normal...she is a dog who thinks that anybody who comes over is there to play with her.
She laid about most of the morning. She seemed like maybe she had a headache or something. She went in her crate again a couple of times. Twice when I picked her up she moved about and tried to get down (not normal until she is tired of me holding her). She was drinking water, did not want her treat, took a small walk and wasn't interested in playing/wrestling with her boyfriend who we ran into. She wanted to go see him, but did not burst off in a run to do so as she normally does. She walked slower than normal, like I imagine an old dog would, or like she'd rather be inside where it was cooler.
I decided to take her to the vet. Temp normal....he pressed and poked her head and neck and stuff, all normal until she snapped at him (she doesn't snap, and this was only a small one...but she never does). She snapped when he pressed on her lower back (his words, not sure where). He said she is having back pain and to keep her on very limited activity (no boyfriend, no runs on beach

--nothing) and he have her Rimidal (sp?) and said to bring her back in 2 weeks.
She seems slightly better. She did eat her dinner and she did want her nightly treats. She didn't try to play and we didn't encourage her to. She just chilled with us.
I hope it's just a sprain or something. I don't recall anthing out of the ordinary. It's possible Charlie (yorkie) pressed on her back with his paw while they were playing. I think I remember that, but I might have made it up. Yesterday, in the rain, she did nothing and I don't know when this started, but it seemed like yesterday. Also, on Sat and Sun we had her out playing lots of fetch with her tennis balls. We play in a ballfield and she runs from left to right field at full speed.
She just turned 4, she is current on her shots. She is never sick and she is almost 11 pounds, she is not thin, but she is not fat either. Yorkiepoo.
That's my story and I guess I'm hoping someone will tell me that sometimes they just get backaches and then they get over it, like us people sometimes do.
As for x-rays. I didn't think of it at the vet. I suppose if she was limping or something, but she's not, she just seems to have an ache or soreness. Do they need sedation for x-rays? Also, this would seem like a new injury and I think sometimes its better to hold off on the x-ray.