Should I get it investigated?

Hi, I'm a 21 yr old female and for the last 4 years have suffered with intermittent hiccups. They're very sporadic, some days are a lot worse than others, but on average I hiccup loudly about once every 15 minutes. In the past 6 months my eyesight has deteriorated; I got glasses and wear them when needed (the optometrist had a hard time finding the correct lens, he said nothing looked wrong with my eyes), but more and more often now I feel like my vision is compromised and feel it feels unfocused. I occasionally (thankfully not too often) notice my eyes flicker, like they move out and in quickly. But in this last weekend there was one occurrence where my vision went REALLY blurred for about 3 seconds and then later that evening/the next morning things seemed to 'flicker', like faint lights being turned on and off. Also in the last month I'm experiencing post-nasal drip and have noticed a difference in my swallowing (my tongue clicks off of the soft-palate and also food is going up my nose). I did suffer with a bad cold before this and had a cough that took a long time to resolve, so I don't know if it's due to that or not.
Are these linked? Should I have it investigated?