Shortness of breathing. An assignment!

Shortness of breathing is felt, for the past one hour. (Since 2.45 pm), today, 1.6.20. It is felt, when I laid down in bed. It continues, even I turned up the sides. Usually, when I wear mask, I do feel this problem. By that time, I keep it, beneath of the nose. Not using in home. Even after climb up over 21 steps, it occurs. No smoking. Instead of rice, I prefer to take only boiled vegetables Iam a vegetarian. No drinking. No Asthma. No chest pain, no fainting, no nausea, not found bluish tinge to lips or nails, or a change in mental alertness . Height-173 . Weight - 84 Kg . Circumferance from the umbilical point -104 cm. While sitting, the same problem persists. While walking in home or in a standing position, IT DOES NOT OCCURS. DIB: 05.07.1960. Retired and non pensioner. If I take rice food, I feel, heaviness in stomach. Hence, most of the time, I do take only boiled vegetables. Guidance solicited. N. Pattabi Raman. N.B. At present, I do not go for work. But, taken an assignment