I have a pulling sensation at & above belly button after Tummy Tuck, can't stand straight & a dimple above my belly button?

Everything you describe sounds totally normal. The dimple is from a suture that will probabl dissolve. It an take a few weeks before you can completely straighten up. Keep following your surgeon's instructions.

Pulling, tightness, and small contour deformities are common after a tummy tuck. Voice your concerns to your plastic surgeon and be patient. These issues will likely improve with time and massage.  Good luckGaurav Bharti

It is difficult to give you a good answer without pictures. From what you describe, this could be part of a normal recovery. Some surgeons like to fix or anchor the umbilicus to the fascia at the 12 o'clock position to enhance the appearance. This may create that dimpling, but it subsides with time. No harm in having it checked out by your surgeon.