Также и тоже are used differently. It has nothing to do with their position in a sentence. It is rather a matter of logic.
You use также when you supply some additional information about the same subject.
E.g.:
Максим хорошо играет на гитаре. Он также неплохо поёт. - Maxim plays guitar well. He also sings well.
Here we talk about the same subject (Maxim). First, we inform about his guitar skills, and then we add some more information about him using также.

Тоже is used when you apply the same information to another subject.
E.g.:
Максим хорошо играет на гитаре. Я тоже играю на гитаре. - Maxim plays guitar well. I also play guitar.
Here we talk about different subject (first one is Maxim, next is I). But we apply the same information to both.

Hope it helps.