Nope u got the conditions abit wrong - both should be harm as opposed to [target=targettarget, help] which means u are trying to cast FS on friendly target,so it won't work Xaru fixed that, u can keep it in a single line with singe /cast that is not a problem(infact u can have more) and spell name is exactly as seen in spellbook (use shift-click if u are nto certain)
Also i have no idea why would u want to target the boss/add but i'm pretty sure empty brackets [] will cast on default target, or in the rare case focus it and use macro with [@focus]. I haven't been healing much lately but i used Flame Shock to keep my haste from totem anyhow so i used it with my favorite taunt macro :
Code:
#showtooltip Flame Shock
/cast [@mouseovertarget,harm,exists][@mouseover,harm,exists][@targettarget,harm,exists][] Flame Shock
Seeing as most healers use either mouseover macros/addons so their mouses are hovering over the raid frames most of the time i see it very practical to use mouseover macro for FS - the order of the [] conditions correspond to their priority so u can move them in the line depending on what u want - as it looks right now it's first at the target of some unit(say tanks, dps in ur raid frames) - this is the most easy one to use as u can use it while healing and u don't really care if u hit a boss or add. Second target of the macro will be enemy u mouseover, 3rd will be the target of ur target(say u have the tank for target) and the last pick would be ur own target. Keep in mind that no matter what u have targeted at this order mouseover targets will get shocked instead if available.
Hope this helped