If the frame is at the very end of the clip, it's not hard to do. If the frame is somewhere else, this is what I do to achieve the pause.

Put the cursor where you want the pause to occur, mouse click the video track at that point and click the diskette icon at the top of the preview window to save a copy of that frame. Use the Split command ("S") to split the video track and then drag the right side of the split video out a few seconds to the right. Retrieve your saved frame and insert it in the gap you just created with the split and drag and then make the still frame as wide as you need it to be so that you have a continuous video track with no gaps.