Is my 13 yr old son old enough to chose what parent he lives with in the state of Texas?

Kids don't get to decide until they turn 18. If one parent makes the right motions for modification with the court then the court can consider as...

Can i retain my former husband`s name after i remarried my new husband?

There is no Family Law requirement to change your name either in divorce or marriage.

Will I be held in contempt if I do not surrender my child over 48 hours past the designated time my ex was supposed to get him?

You might want to get an attorney to read your decree with you. Generally, more than 15 minutes late for the NCP pickup is cause for the CP to make...

What will happen if i committed adultery during my separation with my spouse and the other woman finds out shes pregnant by me?

The outcome truly depends on all of the facts and the substance of the divorce. I'd consult with an attorney about this.

Is it legal if my husband ex wife still using his surname ?

There is no requirement to change names when divorcing. Sorry.

Do I have case?

Sounds like you might have a personal injury case. Talk to an attorney asap. Continue your medical treatments!

Does my power of attorney really mean nothing?

POA does not give you parental rights. You guys need to talk to an attorney about doing this correctly.

Sounds like you are going through the Texas Attorney General's office. Please note that the AG will be there to look out for the State of Texas....

How would I remove my name from a birth certificate if I'm the non biological father?

You'll need to file a lawsuit to determine paternity. It will help if you can name the real father.

Can my ex convince the court to modify my custody and force me to bring children to extra activities?

On the facts that you have described here it is unlikely that the court would modify the decree solely for an after-school activity.