The description seems like you are too skinny and don't like your body type, and at times have low endurance for task requiring muscles to work persistently.
The issue may be connected with, increased metabolism rate or diet concerned.
Next Steps
Please get your metabolic rate assessed and along with it make sure your
thyroid levels are in check and not increased. Next step would be please ensure that your diet contains a good amount of protein and fat along with carbs and aa m. I.e should be balanced diet along with fortification of proteins. Consult a nutritionist for diet counseling
Third issue concerned is endurance. You need to work on endurance training by gradually increasing the number of repetition and keeping resistance to a constant for a while.
Side-by-side you can start off with strength training which will help your muscle bulk to built up.
Health Tips
Please understand that body building depends on various factors other than just diet and metabolism. Get your blood tested and ALL THE VERY BEST . Stay Healthy