I have rectal pain after bowel moments and its easing after a secretion come out from there. is it colitis?

May be hemorrhoids: It may be colitis, but more likely it can be caused by hemorrhoids or a fissure which are painful conditions that can be caused by constipation or really firm stools. These are less serious conditions and can be treated very effectively. However, you should be certainly evaluated in person and they can likely determine pretty quickly what's going on.

Could be abscess : This could be an abscess. Fever, pain, increased drainage are other signs. If this worsens, it may require a procedure to open it up and allow it to drain. The other likely possibility is thrombosed hemorrhoid. If the drainage was bloody or dark red, this is more likely. If it was tan or brownish, abscess is more likely. Should probably see your primary care doctor about this.