I'm 16 5"11 and basketball player i had a open appendix surgrey last month and my wieght is 44 kg pls help me how to gain weight and strength w/o lift?

Eat healthy foods: that are high in calories. Eat 6 meals /day. Sleep at least 8 to 9 hrs/night. Hydrate well w water. Foods to help w healthy weight gain: almonds, cashews, pecans, sunflower seeds, flax seeds, walnuts, hummus, Avocadoes, granola, trail mix, dried fruits, extra virgin olive oil , canola oil.

Exercise is key: You want muscle, and especially you do not want fat simply to meet some subscientific or cultural idea of "the right weight". If you are good at your sport and can see your abs, you are in excellent shape. Eat enough protein, exercise hard, and your body will take care of itself.