I need help understanding this position.

Can someone help explain the computer's analysis for me? I'm really at a loss at understanding the details. So in the position above I'm scored at +1.35 and I played 14.Nxe5 with the idea of taking back my pawn and avoiding a possible Bxf3 and having my pawns doubled in the endgame. The computer considers this a mistake though and I drop down to -0.37. 

However the computer prefers 14.Qc4, Bd6 15.Nxe5, Qc8 (+1.10). I understand that 14.Qc4 exposes the Black Queen to attack by the rook on d1 but why is the exchange of Queens bad in this position? In both variations the pawn is taken back so I'm at a loss at why one is dominant at +1.10 an the other is -0.37.

Thanks in advance for your assistance.

The line Qc4 Bd6 Nxe5 Qc8 then continues Bxf6 and it is black who is suffering structural damage to the kingside pawns. Engine then gives Qf5 as best instead of immediately gxf6 so black is having to make some awkward manoeuvers to avoid his position becoming worse and worse. After Nxe5 Qxd4 Rxd4 things are a lot simpler. In the starting position white is slightly better because of having full development (compare the white rooks to the black rooks) and the pawn on e5 will be recaptured. If you trade off the queens a lot of that slight advantage is lost as there is much less danger in the position. Comparing the queens...either you trade and both have no queen and its equal, or your queen is on c4 and the black queen is on c8. White has the better placed queen so it makes sense not to trade them. (Qc8 also delays black bringing the Ra8 into the game). In terms of interpreting the analysis, I would say +1.10 is not 'dominant' just better. Its a slight advantage (about a pawn) and this can easily be frittered away by some inaccurate play, such as allowing the exchange of queens here. Only at maybe +2.5 and above can you say its a winning advantage. Nxe5 is not bad, and there is logic in your thought process to avoid Bxf3, but it allows black to solve the awkwardness in his position. Its usually better to maintain tension in a position rather than release it if you are the one with an advantage. Likewise usually better to keep the queens on if you are standing better. 

Hi and thank you for your detailed explanation of the position. I definitely see what you're saying now. The variation by the computer definitely maintains blacks problems whereas my line squanders my slight advantage. I'll be honest though its a above my skill level thinking of a position in that way but I can see what you're saying now. Thanks, I was really confused!

No worries. A couple of useful thinking tools... If you have the option to exchange ask yourself whether your piece or your opponents has the better future. Also, look at the least obvious moves first before coming back to the ones which may seem automatic. In positions like you posted it's easy to recapture immediately when there is something better. Often there isn't anything better, but if there is it's these zwischenzugs (in between moves) which can often be overlooked by opponents and give you a strong advantage. The best to you and your chessing 👍

Additionally, do not take engine evaluations too seriously. This is a common mistake especially amongst beginners. Engine evaluations are not always exact and quite unstable. You should rely more on patterns and intuition. 

there is no diagram...

you can grab the pawn either way but the engine line removes 2 defenders from f6 and so you can take the knight and double the pawns in front of the king leaving him exposed.. 

also I'd be reluctant to trade a centralized queen for an undeveloped one.

This is a lesson on good pieces vs bad pieces.

Your queen is nice and centralised. It has good mobility and control over the centre. That's a good piece.

Your opponent's queen is confined to the back rank. It has very little mobility and barely controls the centre at all. That's a bad piece.

You don't want to trade your good queen for your opponent's bad queen. That's why you avoid the trade with Qc4 (and not Qb4??).

Besides, you can always win the e5 pawn whenever you want. That pawn isn't going anywhere. So why the rush? You don't need to capture it immediately. You can harass the black queen a bit first.

After 14.Nxe5 Qxd4 15.Rxd4 Re8 most of the tension has gone out of the position. You have your pawn back, but what else. Material is equal. Black has the two bishops, which might prove to be useful, but it's pretty equal

But after 14.Qc4 Qc8 15.Nxe5, you seem to have more active pieces. Your rooks control the open central files, And if Black makes some silly move like 15,..c5, you have the little tactic 16.Nxf7 Rxf7 17.Rxe7. 

I'm not a beginner, just a weak club level player. I've been playing chess for around 24 years. My OTB rating (when I was still active) was 1420 ACF. I'm just coming back from several years break.