Remember lava burst is an 8 second cooldown so you cant spam it. I made a seperate macro for pvp.

/use 13
/use 14
/castsequence [target=focustarget] reset=4 Flame Shock, Lava Burst

This pops my trinkets shocks and lava burst. I have it on a different button than my pve spam macro above. I also changed one of my shaman to Frost Shock to slow the guy down I am focusing on. I may do two shaman with Frost shock in case one gets resisted. Right now my lava burst are hitting for 4+k x 5. I wasted some cocky alliance yesterday with my above macro.