Many viruses start this way.

Also neuropathies start this way.
I would NOT lie on a heating pad for long periods. This can overstimulate pain sensation in the long run. 20 minutes tops is what works best.

Often people are low in magnesium. Doing physical things that result in pain like this points in this direction.
I'd recommend a good magnesium supplement if you are not already taking one.

I prefer the new Aleve liquigels. This formula of naproxyn is fast acting and long lasting. One capsule of this for me is stronger than RX versions. I use these when my issues flare, and this week they are certainly flaring with the weather changes. I also use Salonpas patches (over the counter) for more targeted areas like the knee, fingers etc. Salonpas put on the trapezius on each side may help. Use only the methyl salicylate ones, they are the best.
http://salonpas.us/
Many people here have tried them and loved them. I use them all the time and buy in bulk at Costco!