Ripping Triceps while Training Traps?

I was working out my traps by doing shoulder shrugs. Now i think i did correct technique- shoulders back, arms straight down. I was carrying only 7 kg per arm, my traps are more than capable of that. However when i shrug my right trap i feel a pulling sensation in my right tricep area. Now its not just any pulling feeling. Its like the kind of feeling when u rip up a sheet of paper. Theres a bit of pain too. Am i ripping my tricep? Is this due to a lack of rest (i did my arms workout the day before) too heavy weights? or what? Theres nothing wrong with my left tricep, yet i train them symmetrically and treat them the same.