Ice: I have a neck wrap that I keep in the freezer. A travel neck-pillow with natural contents is good - it can live in the freezer ( or be put in a microwave for heat ). I've also used small plastic cups with frozen water inside. All these can be applied to your pain over clothing or thin towel if using ice, when pain is getting you down. Experiment to see what location feels best - trigger points can be different for everyone. Sometimes for me, putting ice on my head where it hurts helps. But it can also help to ice my neck, shoulders, scapulae, even upper arms.
Heat: my Dr says use whatever feels best at the moment - heat or ice. Just a comment on heat, it causes tissue to swell a bit. Swelling/inflamation = not good.
so use in limited amounts.
Anne