Hey Britney
Hair advice can be kinda hard to give because not everyone has the same kind of hair texture, so it can depend on that to give the right advice for your hair. But when I was in girl mode, I had really long hair and my hair is thick and wavey, so I used to straighten it religiously! I admit that kills hair, and if you don't get those ends trimmed it will never grow because the ends are dead and your hair will start splitting. So as much as you don't want to, you might need it trimmed if you want it to grow. Also, I was like you, I couldn't go out without straightening my hair, so if you absolutely feel like you need to, then invest in a good flat iron like a Chi and use Chi products with it. I actually still straighten my hair at times and my hair is still soft
As for shampoo, well my mom loved us to have long hair (I have 5 sisters and they all have the long hair) so she bought the horse shampoo for us, sounds weird but its called Mane and Tail (which they have at Wal-Mart in the shampoo aisle) and it gives a good coat and makes your hair fuller, and my hair used to grow like crazy. But really any organic shampoo, as mentioned, can work because theres no harsh chemicals.
I don't know if any of this will really help, but hair can be tricky anyways, so good luck. BTW thanks for the shout out again (; lol