Weak diaphragm - but why?
 

I am a 47 year old mum in The UK who has noticed difficulty breathing when lying down and also experience intermittent heaviness in my chest - particularly the right side. Tests reveal resp muscle weakness - normal mouth pressures but diaphragm function is just 50% of expected minimum. Diffusion is reduced but other lung function tests are within acceptable limits. EMG in March not indicative of any disorder and MG antibody absent. I have had no mechanical injury/surgery nor any other cause that I can find on google so I wonder if anyone else has diaphragm disorders or what the possible causes could be?

Thanks for reading! Clare