My wife’s chest is burning and short of breath after dialysis???

Hi everybody. Thanks for all of your responses. My wife has had a lot of time consuming issues with the dialysis lately and I was just able to get back to your site. She has been on in-center dialysis for 18 months after a transplanted kidney quit working. She is on the machine for 4 hours three times a week. She developed pneumonia in February involving 2 ER visits and two different sets of antibiotics over a six week period. The first was Zithromax with an IV at the hospital and six 250 MG caps to be taken 2 after each of the next 3 dialysis treatments. One month later she was back at the ER and they gave her Levaquin with a 750 MG cap and kept her overnight for observation then released her to take Levaquin 250 caps daily for five days. In each case her symptoms were difficulty breathing, burning in the front chest area and sore rib-cage. All of the major heart / lung testing and labs at the ER visits were OK and they had trouble seeing any fluid in her lungs. She was back at her GP doctor Tuesday and he said the pneumonia was gone. She had three quite good dialysis treatments this week including this afternoon. Her hemoglobin this week was 10.6 and Oxygen reading was 97%.
The problem is she has felt lousy most of this week with the difficulty breathing, burning in the front chest area and sore rib-cage all back …. and fatigue. The GP said he thought it could be extra carbon dioxide in her blood / system and to try to slow down / control her breathing. The manager / nurse at the dialysis center today said that her problem was not dialysis / ESRD related. She has been through a really complete physical work-up for a new Kidney TX over this same six week time period so we are quite sure that this isn’t a life threatening situation but very uncomfortable and troublesome. Really appreciate that you have this site and would welcome any comments on what we should do next. Thanks for having this site for us!!! Mattie130