Greetings. I Am A Non-smoking Male, Age 44, 5'3'', 195

Greetings. I am a non-smoking male, age 44, 5'3'', 195 lbs. For two weeks I have been having chest pressure on and off. It is alleviated when I re-hydrate by drinking water...only, I can't seem to stay hydrated, and keep losing all the water I drink. Thus, two questions: would the chest pressure be caused by dehydration...and why would I be chronically dehydrated in spite of always drinking water? Thanks.