Hi there and welcome to the AZ. Physical pain is very common to people with anxiety - mostly because anxiety causes us to tense up (even if we don't think we are feeling physically tense) and muscles become tight. And usually when high levels of stress and anxiety creep in, we stop doing healthy things like exercising, stretching, and relaxing (which we should be doing) and everything becomes tight. And muscle tension is not something that goes away overnight - if you do have that night where you don't feel anxious. Being diligent about stretching and making yourself exercise, even when you don't feel like it, are some of the best things you can do for muscle tension. I would encourage you to do that.
Most definitely do not google. That is a health anxious person's worst nightmare. Google cannot diagnose you with anything (and neither can you, unless you have MD behind your name) so stop trying - it is one of the best things you can do for your anxiety.
I get those moments of ruminating over death and chronic illness (and I have been dealing with that alot more recently as it has come up with people I know in my life). Anyway, I agree with you that positive thoughts are the best way (that I have found) to combat it. I really like positive self talk (I am healthy, I am positive, I am happy - as much as I can think of) and doing that many times a day. The more I do that, the more I find it helps with those negative, ruminating thoughts. When I stop, or am too lazy to do it, the thoughts will return. Also being social helps me with those thoughts - not just being around people but hanging with people I can really talk to - it's another form of distraction. I guess that's what it comes down to, distraction - a retraining of the thinking process.
Another thing I have used for physical, muscular pain is a massotherapist. That has helped alot. It helped convince my mind that the soreness and weird sensations I had because of the tight muscles was exactly that - tight muscles. Maybe give that a try. Hope this helped!