Read your profile. You've been in pain awhile, are you on pain meds? Have there been any changes in them recently? Have you been unable to work, or are you facing retirement? Has your family situation changed? What I'm getting at is there might be a trigger to this if you can find it. It also could be something physiological that's new not involving your pain issues. Medication used for chronic pain can cause emotional problems and nutritional deficiencies. Are you able to exercise at all to burn some of this off? The suggestion above to meditate is a good one; so might be hypnosis, as it also has been found to help with chronic pain. I feel you -- I'm 65, and I'm also suffering from chronic pain, but in my case I don't know why because I've been an anxiety sufferer for years and the medication for it turned out bad for me, an unusual thing to happen. But I think when we get to our age (your profile says you're 63), it becomes harder to see things ever resolving. That can also be a trigger; it's driving me nuts because exercise has been the only thing I've been able to do that's fun and I'm now hurting everywhere. Again, I'm looking for triggers for you. Also, the Shalom suggests you belong to a faith community, do you have one you can go to for support? As for what to do, therapy is a good start, but if this gets out of hand your therapist is going to suggest medication. Be ready for that possibility.
Anxiety and depression go hand in hand feeding off each other in a vicious circle and escalating the problem so it can be impossible for the poor victim to figure what is the problem. Both may be a problem. For example if you have a health issue it gets depressing being sick all the time which causes the anxiety to increase which makes the dep worse because life is even more miserable. Etc.
You say there is no reason for the panic which can happen too, however if you can find something interesting to occupy your mind it may help. Meditation, philosophy, volunteering are possibilities while you wait for therapy. How long do you have to wait?