Hi welcome to HCM,
The first symptoms Ankylosing Spondylitis
are typically chronic pain
in the middle part of the spine or sometimes the entire spine, often with pain referred to one or other buttock or the back of thigh from the sacroiliac joint
.,which may itself present as dyspnoea(difficult breathing ).
However ,the drug which you are taking is an agent for immunosuppression
,the treatment of choice ,but can have side-effects like thrombocytopenia
and acute dyspnoea .
you must consult your doctor again before changing the medicine or stopping all together .
hope i answered your query .