Should I pay Income Tax and NIC for sold SIP shares via Self Assessment?

[A1taiR]

Hello,

My employer does my taxation through PAYE. I've recently sold some shares from my SIP (Share Incentive Plan), which I held for less than two years and the money was paid not via payroll. The gain from the sale is less than AEA (Annual Exempt Amount) so I am not liable to Capital Gains Tax. However, I should pay Income Tax and National Insurance Contributions. Should I do that via Self Assessment?

Thanks