Is the pain in my neck related to my thyroid? it hurts to touch

Probably not: There are many causes for muscle cramps, but given your age and the fact that you're working in heat, my first thought would be dehydration or an electrolyte imbalance. I would go to your primary care physician and report these symptoms. He or she will most likely order some blood work to see how your electrolytes are doing. Needless to say, when you're out working in heat, it's vitally important.

Possibly: Thyroiditis, or inflammation of the thyroid gland can make the thyroid gland tender & sore to touch. But lymph nodes in the neck can become swollen and inflamed too. Best to see your doctor to see if the area that is sore is where the thyroid gland sits. Thyroiditis can also cause temporary abnormalities in thyroid hormone levels, so your doctor may ask you to get blood work to check on this.