I get acid reflux when I run if I am properly hungry (weird, I know). Bananas also cause it.
Definitely worth going to the Doctor. My Dr put me on tablets (I also can't remember what) when it got a bit chronic because it meant that I was more susceptible to throat infections and I kept losing my voice.
I'd suggest that you do need a bit more foundation in terms of distance covered... but if you can, start with getting a long run done once a week (1.5 hours ish).
The tempo run is a great addition - I would suggest that if you are training for 10km, its not long enough! Can you do 2 x 20 minutes with a 5 min jog, or 30 mins and then 10 mins?
Finally, I would suggest that you do a bit more variation in your speed work - 8 x 4 mins is a tough session so well done But 4 min reps aren't going to work on your top speed. You obviously have alright basic speed if you are running 16:30 for 5km. But to get quicker you could consider doing more, shorter reps (wouldn't bother with anything less than 400m if I were you though). e.g. 15 x 400 with 1 min rec. There's loads of sessions - possibly doing speed work with a club would help add variation?
If time pressed, try to focus on 3 key sessions per week. e.g. long run, tempo run and speed work. If you have to miss anything, try hard to make sure its not these.
I have read a couple of great self-published books. But I generally feel that most (not all) of the time, a publisher kind of acts like a sieve for quality in writing (narrative, structure). It then also helps clean up the grammar and sort out factual errors, which I find very distracting when I read.
There's another thread on this on the beginners forum too, which you might want to read. For me, it varies depending on the make of the shoe, and I personally don't listen too much to the "500 mile" rule. I usually get around 800 miles out of a pair of Asics. I just changed to Mizuno and I love the shoe, but have trashed the forefoot in less than a month - thats 300 miles. Adidas are also fast wearing for me. But other people with different gaits will have different experiences.
Shoes generally just feel spent when they are at the end of their useful life. You might feel the stones on the road a bit more, or like you aren't getting the right support from the uppers. The soles might be worn away, or if the white foam is cracked or wrinkled. Usually for me its a combination of factors. Be careful if you pronate or suppinate and you are wearing away one side more than the other - this will exaggerate the effect on your foot.
If you are running high mileage, or twice per day, you might find that you can prolong the life of a shoe by alternating pairs.