Sudden Attacks of Pain - No Visible Injuries

[Megga156]

I have a little Shih Tzu Maltese - she is about 13.

She has never cried / winged / complained in the past unless someone treads on her paws etc.

Over the past week, the following has happened:

1. While sleeping in the night, she has been screeching / crying for around 3-5 minutes
2. Over the past week her right leg has been getting worse, she can only walk on 1 leg and limp (as if her leg / paw is fractured / broken / arthritis?)
3. While sitting by herself, she will start to screech - without any human contact
4. When she starts these episodes, we try to calm her down but human contact does not seem to stop the episode

So, I was thinking sprained leg / thorn in her paw etc - I have been massaging her leg and she does NOT screech. If there was something wrong with it, surely she would not let me touch her leg let along not complain.

She walks around limping on it and can't put much pressure on this leg. But when I touch it, she is fine with it.

So my thoughts were:

1. Cramps (not enough Salt / Water?)
2. Arthritis

Has anyone had this issue before?

Everything else about her seems normal.

[mmews21]

Have you found any results? Im having the same issues with my senior dog with no results from the vets.

[Misfits4Me]

Right Front leg or back one?

[Margot49]

Actually, as a side thought, a friend and I were just talking today about a neighbor I had that asked if I would look at her dog as she had a sore foot or leg.  I looked the dog over to find a dew claw nail had grown long enough to grow back into the pad.  She didn't even know those nails were there.  
I assume, by now, you know if your dog dies or not have dew claws, ESP since it is a long hair breed.  Wouldn't hurt to check.

[Margot49]

Unless it is obvious, sometimes it can be very hard to determine the source if pain in a dog.  Something is obviously hurting her and, considering her age, it could be arthritis or even a problem with her spine or cervical area.  You feel any type of lumps on or under the leg or in her armpit areas?
If it continues, I would take her in for a Vet exam to see if they can determine the cause and perhaps some medication is needed.