i sometimes feel suffocation in crowded places, my Bp is allright ,at the same time i feel that my legs are giving away.

There is a very good possibility that nothing is wrong with your heart. You have most probably developed a phobia of crowded places akin to agoraphobia (extreme or irrational fear of crowded spaces or enclosed public places.) I believe that you should at the earliest talk to your doctor. There are very good medications that can resolve this as well as psychological counseling that might help. Take care and talk to a doctor where ever you are.

(Note the use of word such as 'possibility' 'probability' etc. The above statements in no way should be considered as final medical advice by a Medical Professional)