Have you been tested for your blood sugar? You say while on phone. I assume you mean while you're talking on the phone? A lot of people are getting all manner of nerve and joint pain and muscle pain from poor posture from using computers and especially cell phones. For example, hanging the head down puts a lot of extra stress on the neck. Often the back isn't straight, putting stress on the entire spine, including the neck. This can lead to pinching of nerves. It could be poor circulation, but if it was, I'd think you'd have other parts of your body bothering you as well. Eating poorly and being overweight catches up to you as you age. That's why I suggest getting a physical and seeing if your blood sugar is normal. You might be developing Type 2 diabetes or have a blood sugar problem that is short of that, which can lead to circulatory and nerve problems. But most likely, it's your phone using posture since it happens when you're on the phone. It could also be carpal tunnel. See your doc and get a thorough physical. If that's okay, see an orthopedic surgeon and see if you might have carpal tunnel, or your regular doc might be able to tell you as well. If so, occupational therapy for your hands will probably fix it and teach you proper phone posture. Peace.