Why can't I inhale completely?

I don't know what causes this, as it seems to happen every once in a while and at seemingly random occurrences, but I can't inhale all the way. To better state it, I can't get a satisfactory breath. And it seems like sneezing, coughing a lot, or any other throat-involving issues cause it. Other than that, it just seems to happen randomly. Such as right now, I can't really inhale all that much without feeling like my throat is closing up when I inhale. I haven't asked my doctor about it, and I know for a fact I don't have asthma. Is it just summer allergies, or do I need to go get my lungs scanned?