Thank you for the reply.
I know it can be very difficult to watch our pets age, especially when you feel they may be suffering and you are not able to provide relief.
It can be a challenge to differentiate her symptoms as due to pain or other possible causes. Degenerative diseases such as degenerative myelopathy (link here) can be debilitating and progressive and do not usually respond to pain medications. Fortunately, they do not usually cause pain though, but only loss of function. Other conditions that cal lead to the restlessness and the panting can be behavioral in nature.
I would wonder if maybe she were starting to show signs of a condition called cognitive dysfunction. It is a condition that we see in older dogs with signs that vary from dog to dog. For lack of a better comparison, it is similar to Alzheimer's disease in humans. Here are a few links with more information:
CDS in dogs
Here are some of the most common signs seen, but there are others as well including restlessness and panting:
general confusion - your pet doesn't greet or seem to recognize you as before, your pet gets 'lost' in the yard or house
inappropriate vocalization - barking or meowing in the middle of the night, or for no 'good' reason? (I know, some dogs don't need a reason to bark.)
getting day and night mixed up - sleeping all day, awake all night?
confusing indoor and outdoor - a previously housebroken pet soiling in the house?
personality changes - i.e. a formerly outgoing pet becoming timid or aggressive?
I have seen a good number of dogs affected by this and all have exhibited different signs, especially in the early stages. I would have your veterinarian perform a thorough physical exam to make sure there is nothing else going on.
Some dogs I have seen have responded to diet change alone. Hill's b/d diet is a good choice. LINK HERE If not, the medication called Anipryl® is very effective for many dogs.
I generally start with supplementation first (+/- diet change to b/d if there are no other dietary restrictions needed). I usually recommend increasing the omega 3's in the diet as well. The active ingredient of fish oil is EPA (Eicosapentaenoic Acid) and DHA (Docosahexaenoic Acid). You just want to make sure you are seeing those on the label as an ingredient and not just the words "fish oil" as these are the important part of the fish oil and not all fish oil capsules have them in it, especially the cheaper ones. Aim for 180mg EPA and 120 mg DHA per 10 lbs body weight daily. There is a large range of safety and it doesn't have to be that amount exactly but this gives you some guidelines.
There are various additional supplements on the market to help with brain health. The three most readily available are: Cholidin, Senilife and Novifit. As far as which supplement to try first, I do not think there is any general agreement on that. Between the cholidin, senilife, and novifit I would make my decisions on which to use based on cost, ease of administration and availability. I do not see a problem with using them all if cost is not an issue and you have a dog who doesn't mind taking oral supplements. There may be more benefit to starting with multiple approaches for a greater combined effect and backing off to a minimum effective combination if you get a favorable response. It is not always easy to track response as the symptoms can be variable and intermittent.
I would add the Anipryl if needed for better effect or as the cognitive dysfunction progresses.
Urinary incontinence is not uncommon in older female dogs due to weakening of the urethral muscles and leakage of urine. The drug called phenylpropanolamine can be very helpful if this is occurring and if she has not tried that, may be worth mentioning to your vet.
Maybe adding some of these other medications or supplements will help. It is difficult as her symptoms are likely not due to just one thing, but more likely a combination of conditions.
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.