So i saw that the LCS pros pick Shiv on her...But honestly in Solo queue it's another stor
I really appreciate if you can tell me when should i pick Shiv and when Phantom cause my head hurts of thinking -
That one guy that everyone
disregardable1 votesIn the LCS they'll do that if the enemy ADC does it, just to prevent a gold deficit.
In solo-queue, you only want to get it if you're losing lane. Get Avarice Blade 
first and hold off upgrading it to Shiv until you've got a bit of gold from it.
Shonjl1 votesI would personally say Phantom since Shiv only helps clear waves, which Jynx has very easy time due to her rockets. So I would take the passive and just higher stats on Phantom over it.
Only time I see Shiv being more worth it is on champs that have poor waveclear like 
or 
