Pressure after septoplasty and turbinate reduction may be due to allergic rhinnitis, recurrent or chronic sinus infections, or even contact neuralgia from the turbinate and edematous mucosa. A formal nasal endoscopy would help to determine the cause of your troubles.
Dear loulou1985: Without physical examination, CT scanning and nasal endoscopy a precise answer is impossible. Please return to your surgeon and explain the problem. Remember allergies are treatable not curable. If there is a physical obstruction, imaging and endoscopy should be able to find it. If you are unhappy with your surgeon please see a board certified otolaryngologist, facial plastic surgeon or plastic surgeon with sinus surgery experience. Hope this helps and good luck!