I'm a teen that's struggling with her weight can anyone help?

I am a 17 year old girl that's struggling with my weight. I'm 5 foot 10 and 220 pounds. I have asthma as well as the beginnings of juvenile arthritis in my knees so it makes it hard sometimes to work out. Are there any tips that can help me boost my matabolism so my body can burn more fat naturally without me taking some weight loss drug or starving myself?