When i pee i still feel like i have few drops in my penis which are not getting out but sometimes when i pull up pants then it later drop in it. why?

Here are some ...: What you observed & described is so-called postvoid dribbling, which commonly happens the elder men, but occasionally to the younger as well, especially those with urethral stricture. Nonetheless, milking urethra by manually wiping and pressuring the whole urethra from the area behind the sac to the end of penis for 2-4 times until dry after each voiding will help; try it out and let me know how..

You need: to tighten your sphincter muscles at the end of urinating to get the last few drops out. If that doesn't do it, you may need to put pressure at the base of the penis with your hand to empty all the urine. This is called milking the penis.