I am unable to take in deep breaths unless I try really hard. Seem to lost the function. Are my lungs damaged. Any. Other possibility?

Need full lung eval. Most of the time when you cannot take a deep breath it is because a discomfort (mainly pain) prevents you from taking a deep breath - a muscle strain, rib contusion, lung problem or gastrointestinal issues can cause this. In the absence of such issues it is rare but possible that pure motor weakness can cause you to feel this way - you need a full evaluation at a doctor's office/.