I'm a 24 year old male, tall and kind of underweight (around 130lbs). My family has a history of heart disease; my father and his mother have had heart disease and needed heart surgery. Many other family members have had high blood pressure in their past. I currently have some stress in my life being unemployed, trying to find a job and I am running a home business that requires long hours at the computer so I don't get much exercise, which is something I'd like to change. My diet is relatively healthy with a mix of meat and vegetables, some fruit, occasionally (maybe 3-4 times a month) I eat out / eat foods high in fat and sodium, but not very often. Though as I teen, my diet was much worse.

Recently I have been having symptoms of numbness and light pressure under my left armpit and an occasional sharp pain near the left side of my chest. I don't feel that large amount of pressure on my chest, most describe when having a heart attack, but I do feel what Id describe as numbness. I've also noticed sometimes under my left thigh, Id get a tingling / numbing feeling.. These symptoms have come and gone over the last few months and I never really found them to be alarming until last night, I noticed these symptoms again and started to worry. My feet began getting a cold sweat and I had shortness of breath.. Needless to say, this made me feel even more worried.

I'd like to know it is possible that I am having panic / anxiety attacks or if I am having heart issues.
How possible is it for me to be experiencing heart problems at my age? What can my doctor do to test if I am having heart issues?

Thanks.