Stop Lamp On Braking !!!

[SilverSpear]

Something really weird is happening in my car guys, yesterday while i was driving, i hit the brakes and... the Stop Lamp light came on. Arrived to my destination, i placed a bottle of water on the brake pedal and went to the back to see which is the one. it was my side taillight bulb. I went to an electrician and bought a new one, everything worked perfectly except that D@MN STOP LAMP blinking !!! i replaced the bulb by another one, still the same even though my taillights are working perfectly both on idle and in braking, the side markers too... the third taillight also... what could it be more than that???