Since when are your symptoms?
Do you have breathlessness on lying down or on physical exertion like climbing stairs?
Do you have loss of appetite, recent increase in weight, lethargy, cramps, joint and muscle pains?
Any significant past medical illness?
Are your periods normal?
Are you on any kind of medicines?
The possibilites to look for your symptoms would be;
1) Osteoporosis; a calcium deficiency can involve not only bones but also the muscles. This can cause chest wall weakness.
2) Spinal radiculopathy
3) Iron deficiency anemia
You should get following investigations done;
1) Serum calcium
2) Anemia Panel
3) Dexa Scan
4) Chest x-ray
Please feel free for your follow up questions.