These days I get a painful burning in penis after ejaculation and feels like I need to pee but itsa drop or two of urine. Why is this happening?

Unusual. Your symptoms are suggestive of prostatitis. However, common bladder irritants, such as caffeine, alcohol, and spicy foods can cause a burning, need to urinate sensation. If the symptoms persist, you should visit your doctor.
Prostatitis. You most likely have a prostate infection and need antibiotics.