Do I have an ear infection? I get irritation, itchiness and a feeling of blockness. I also get discomfort listening to headphones in short periods.

Q-tip usage? The most common cause of itchiness of the ear canal is dryness. Compulsive cleaning of the ear canals with q-tips is the most common cause of dryness of the ear canals. It is a misconception that the ears must be cleaned. Cerumen or wax is normal and has anti-bacterial and anti-fungal properties. Wax always migrates from deep in the canal to the opening of ear canal. Don't push the wax back.
Probably you do. Irritation & itchiness are often symptoms of an external ear infection, treated with antibiotic ear drops. Feeling the ears are blocked and discomfort while using your earphones, could mean it is a middle ear infection, possible as part of a sinus infection, requiring on oral antibiotic. Your gp should be able to DX and rx. But if it is a persistent problem or hearing becomes decreased, see an ENT doc.