Jill,Sorry to read of your problems with pain and spasms. Very cold and very hot beverages may trigger esophageal spasms so you will want to avoid either extreme.
You could talk with your Dr. re increasing your Valium, however, another med that works for some people is Trazodone. Trazodone an antidepressant that reduces visceral sensitivity, has also been shown to reduce chest pain symptoms in some patients with spasms.
Just a couple of thoughts for you this morning.