can his breathing problems be re: phrenic nerve

My husband had gastric bypass July 2007 lost 186 lbs. In may 2008 he had his gallbladder out. both procedures
were lap. Since his gallbladder surgery he has been short of breath, no change in energy level, blood gases
normal, all lab test normal. Pulmonary stress test said he was not active enough. But he works out 3 times a week for several hrs.  Heart cath negative, CT of chest showed a couple of enlarged lymph nodes 1-3mm. He also has a hx of frozen shoulder and bone spurs in his spine. He can not take a deep breath, and said he feels like he is breathing through a straw.
No inhalers help, sometimes sitting way forward helps, eating makes it worse. O2 sats stay 100%.
The Dr said looking at his tests he is the picture of health and he is 52 yrs old. Can this be anything connected
to his phrenic nerve. No one can find anything wrong, and the V A said they doubt the phrenic nerve has any
thing to do with it. He also fell off a ladder after gallbladder surgey and landed on his back. they have not looked at nerve damage before.
We do not know where to turn.