Salaams sister
you should try stretching your back first.
Try this - its a basic yoga exercise
Stand straight, feet shoulder-width apart, feet flat on the ground - no shoes.
Slowly reach upwards taking a deep breath in, arms raise straight up and in line with your ears. Reach up as far as you can and look upwards - do not go on tip-toe. Hold it there for count of 3
Slowly bend forwards and down, arms outstretch, breathing out as you go. Make sure u go slow
keep bending down to reach your toes - dont worry if you can/t.
hold it there for count of 3.
Slowly stand up - again, must be slow - until you return to normal standing position.
Repeat whole exercise 3 times.
Each time you do it you should be nearer to touching your toes as you open up your back and chest with the stretching. Make sure all movements are slow and gentle, doing the deep slow breath in and then out.
hope that helps insha'allah
Wasalaams