A. Lung involvement in rheumatoid arthritis is uncommon, but can actually occur as a result of several different things. All of these things can produce the same set of symptoms - typically cough and shortness of breath - and if not recognized and treated appropriately can become both progressive and severe. The same inflammation that develops within the membranes of joints in rheumatoid arthritis also can occur within lung tissues. In addition, the nodules that typically occur beneath the skin in RA can also form within lung tissue. Two of the most serious forms of lung disease in RA actually occur as a complication of drugs used to treat the disease. Methotrexate can be associated with a rapidly and potentially very severe, progressive lung disease, and patients on this drug should be aware of this potential complication and be advised to notify their physician promptly should they develop shortness of breath. Many of the disease-modifying antirheumatic drugs (DMARDs) - but in particular the biologic response modifiers (BRMs) - increase the risk of infection and can cause pneumonia. Individuals taking these drugs also need to be cautioned about notifying the physician immediately should they develop shortness of breath and fever.

Take Lung issue seriously.... See your MD ASAP.  I know that there are some of the RA meds that you should not take if you have lung disease.

Not to scare you but my sister was chronically ill with lung disease and RA for over 30 yrs.  She recently died of respirtatory failure after getting pheumonia.  She could not take many of the RA drugs.

Get better soon.