I have recently learned that there is much disagreement on the subject of reclining seats, with angry and vociferous groups protesting that either a) the airline makes the seats to recline, they've paid for their seat, and they should jolly well have the right to recline them whenever and for as long as they like, with the possible exception of during meals; and b) people who insist on reclining their seat, especially on short flights, are ignorant boors who have no consideration for others. There are sub-groups of the very short or very tall; the rich, who can afford to fly first-class where everyone has plenty of room to recline as they please; the obese; those who must work on their laptop computer for every minute of the flight; those with babies on their laps; and on and on. There are even devices sold that may be surreptitiously inserted into the seat in front of you to prevent it from reclining.
That said (!) "put my seat back" is fine, as is "recline my seat." "Person sitting in the back" usually means the last row or rows. "Sitting behind" needs an object for the preposition; "the person sitting behind me."
"Excuse me, but now that the flight attendants have turned off the lights, I'd like to recline my seat."
"I'm sorry, but as you can see I'm six foot four, and furthermore I'm working on an important presentation on my laptop computer while breastfeeding my infant. If you put your seat back, I will be extremely inconvenienced."
I read some pretty horrifying stories about people slamming their seats back during mealtime, sending lasagne and hot beverages all over the person seated to their rear. Or damaged laptops. I think there is something to be said for at least checking behind you before you recline, which I must ashamedly admit I have never done (hey, I don't fly very often). But as you say, except for the poor souls in the very last row, you can recover any room "lost" when the person in front of you reclines. If you truly have a medical problem, are very large, etc. it would be best to get a bulkhead or just cough up the extra for business class.
Of course, the real problem is airlines shoving seats that were meant to be 26" apart only 21" apart (or whatever it is).