Hi You may be having DNS, which might be the cause for your nose block. Sneezing may be because of some allergy. Headache may be because of the blockage of nose or sinusitis due to the cold. I suggest you to go for nasal checkup, to rule out DNS or nasal polyp or hypertrophy of the turbinates, which all cause nose block. Homoeopathy can give u good results in allergic conditions & polyp etc For DNS,  u may need surgery