My 23 Yr Old Son Had A Spontaneous Pneumonia-thorax In

My 23 yr old son had a spontaneous pneumonia-thorax in November of 2016 that resolved without a chest tube. He is currently experiencing occasional shortness of breath and a tightness in his chest. The past two nights he has not been able to fall a sleep on his back. He told me that he can only sleep on his side, and is not sure if he should be worried.