Yes lowering of blood pressure can be related to difficulty breathing, but not to bone enlargement of nostril.
So this difficulty breathing can be due to many causes. First give a detailed history:
Patient age?
Is it related to exertion?
Is it continuous or episodic? If episodic how many episodes in a day? How long an episode lasts?
Anything that relieves the condition?
Anything that makes the condition worse?
Is there any swelling of the feet?
Does it occur at any particular time of day like morning, evening, night?
Is there any fever?
Is there any rash?
Is there any cough? If yes is it productive or dry? If productive how many tablespoon of balgham? If balgham present any blood with it?
Is there any weight loss?
Is there any decrease in appetite?
Any history of allergies?
Any history of GERD(please see internet for meaning)?
Any history of blueing or reddening of fingers?
CBC wouldn't tell much. Before going to any doctor at least get a chest x ray done tell lab to do AP and Lateral view(go to a good reputed place with digital x ray machine). Also get an ECG done. Also get a spirometry also called pulmonary function test done. This spirometry is only available in AKU, Liaquat national or south city. Or you can get spirometry done free of cost if you have contacts at civil hospital.
Looking like most probably an allergic condition like asthma as there is history of nasal bone enlargement which mostly is a polyp.
For good doctors go to:
General medicine: Aga khan hospital (Dr. sara sajid, Dr. sobia ghazali), south city hospital (Dr. junaid patel),
Chest specialist: Aga khan hospital (Dr. Ali bin sarwar zuberi, Dr. Murtaza Kazmi), South city hospital (Dr. javed husain), Liaquat National (Dr. Syed Arsalan)
General Medicine and Chest Specialist: National Medical center (Dr. Salahuddin Afsar)