If the mother doesn't let me see my daughter and wants me to pay child support what do I do?

These are seen by the Court as 2 separate matters.
You must continue to pay the support.
If you have a court order, then file for contempt;
If you do not, then file for one.
Change of custody is a complicated matter.

If you have questions, contact me at 978-749-3606.

The court will order you to pay child support and during that action you can request that a visitation order be entered as well.

DISCLAIMER: This answer is provided in response to a "hypothetical" question and provided for general, informational purposes and does not create an attorney/client relationship. The information presented is not legal advice and may change based additional information and research. It is recommended that you speak to an attorney to discuss your specific legal issues.