There are different opinions about answering amein to the chazzan’s recitation of the beracha of ahava raba (or ahavas olom), before k’ri’as sh’ma. Common custom seems to be to conclude the beracha together with the chazzan (thus avoiding the issue–since when when one does that, the din by almost EVERY beracha is NOT to answer amein.)
If you conclude your beracha before the chazzan concludes his, you should answer amein.
(For those of you who may be interested, the Rav always finishes before, and answers amein.)
A possuk in this week’s sedra teaches us the importance of having a mokom kavu’a (a set , regular, place) for davening. There are many explanations for this, and many of them focus on the importance and dignity and aura of formality it imparts to one’s davening. And you’re still talking and texting and kibitzing?