Had a dry cough with back pain for 3.5 months. Chest ct, xray, bloods and lft all normal. What could this be?

Top 3 causes... of cough are asthma, post nasal drip and GERD. None of those would show up on the tests you've had. You need a pulmonary function test to look for asthma and the easy fix for the other two are are over the counter treatments.
Dry cough. You may have an allergy causing asthmatic problems. See an allergist for evaluation and possible treatment.

Related Questions

Normal chest X-ray and VQ SCAN. Normal ekg. Chest and back pain, gurggling sound, short of breath, dizzy. Also tachycardic and dry cough. Please help.

Possible asthma. Please see a board certified pulmonary medicine expert ( pulmonologist)-ASAP- Unable to diagnose online; however, very suggestive of bronchospasm with superimposed viral or bacterial infection. Read more...
Need re evaluation. I assume you have been to the ER and were discharged. A serious cause for your symptoms seems less likely as your initial tests were normal. Among the less serious causes for such symptoms is the possibility of a chest cold and superimposed panic attack with hyperventilation. But if your symptoms persist you need to be re evaluated to determine the proper diagnosis. Return to the ER if needed. Read more...
In-Person Evaluation. You need further face2face evaluation by a physician. Sounds like you are in the middle of a work-up. Are you an inpatient or is this evaluation being done as an outpatient? Sounds like you are looking for a second opinion? Too much information is required to properly second guess your current work-up. Online is not appropriate for this purpose. Read more...

Slight dry cough 3 months & up right back pain. 3 clear xrays, bloods and lft. All normal. Really worried it could be lung cancer.

Probably not. In a 35 year old non-smoker, lung cancer would be rare. A chest ct is a better test than a chest xray because it looks inside the lung tissue better. But, ask your physician if he/she recommends it. Read more...
Probably okay. If you are a non-smoker and cxray okay. Next step is ct lung if concern persists. Read more...

Quit smoking 14 years ago. Slight dry cough 2 months, up back pain.2xrays, bloods, lung function test. All fine. Seen specialist who suspect asthma. Lc?

Chronic dry cough. Your specialist might be right. It looks like you have been seen several times by your local physicians and were throughly evaluated with lab works and imaging studies. If your lung function test showed signs of airway obstruction and a significant response to bronchodilator challenge, you have a diagnosis of asthma. I suspect your specialist already did this test. Good luck. Read more...