What Causes Pain In Throat And Chest During Swallowing?

Sometimes when I swallow (maybe one time per week) when bending over at a sink I get a very painful sensation in my lower throat/upper chest. It feels as if the water has not gone down and is actually expanding. Sensation lasts for less than a minute. I can breath, but talking would be difficult. Only happens with water, never food. I'm a 49 year old male, excellent health and excellant fitness condtion, no known health problems.