Thanks for the query to H.C.M. Forum.
You mentioned that pain is on the right side ,but where ?
Is it in abdomen ?
You mentioned two things that pain is more after lunch & there is breathlessness .
So these two things are related.
May be due to pain in the liver
Lower part of right lung ,
Consult a physician and get his opinion .
Get in ultrasound
of liver and X ray
chest PA view.
Take treatment according to situation.