The parietal lobes contain the sensory functions, and association areas. Therefore when you feel a sensation in your body it is processed within the parietal lobe. The association areas help to intergrate functions. The non-dominant (usually right side) is involved with the underatanding of emotion, and the dominant side helps with calculations, left/right descrimination. Also, the language area which allows us to understand verbal language is within the dominant inferior pareital lobe in most people.
Neck stiffness could be due to a lesion in the cervical spine. This can be evaluated with a MRI of the cervical spine.
Regarding the acid reflux, I am not aware of a specific region which would cause these symptoms. Therefore, I would discuss this with your primary doctor and have it evaluated. You were not recently treated with steroids? This could result in acid reflux. Good luck