Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answer updated 1 year ago

Yes. Recommended Prayers especially Salat al-Layl ( Night prayer) is highly recommended for every one including those who have unfulfilled Qadha  prayers on them. No doubt, the reward of performing Qadha prayers is much more than the reward of recommended prayers. 
You must perform every prayer within its time and never miss any obligatory prayer.