Hi anyms and welcome.
I am sorry that you are currently experiencing this worry...and for the awful attack that you went through last night!:(
When you say relatively healthy...do you deal with any other health conditions that could be causing or adding to this issue? Have you had a recent health screening?
If you are not dealing with another CI (chronic illness/condition) and you have had a recent check up...then you can most likely safely assume that you are having an anxiety symptom.
Random unexplained pain can be one for those issues that comes up from time to time.
The thing is, as anxiety sufferers, we tend to fixate on the issue, adding to our anxiety....which you guessed it...perpetuates the symptoms. It can be a hard cycle to break.
Here are some great coping skills to try for some relief. If practiced everyday, these are really effective.
Self Help sites with breathing/relaxation exercises instructions
Panic attack relief exercises:
http://www.healthcentral.com/anxiety/c/73076/34334/breathing-lessons/
http://www.healthyplace.com/
http://www.stress-relief-exercises.com/
http://www.ehow.com/video_4405003_breathing-exercises-panic-attacks.html
http://www.psybersquare.com/anxiety/panic_relax_I
You may also consider talking to your doctor about other treatment options such as medicationa and or therapy if you've not done so already...and you feel you need more help.
Post with us anytime. We do understand and care...and support is key!
Scaredy Cat