Should i have a severe toothache after a 4 root canal procedure on a mauler and if so, for how long?

Maybe: It is not uncommon to have some discomfort or pain after a root canal, but it generally shouldn't be "severe." the amount of discomfort one should expect depends on several factors, like how severe was the tooth infection, how difficult was the root canal, how was the bone around the tooth affected. You should contact the dentist or endodontist who performed the root canal and get their input.

Root canal: It's possible to have post-op pain in a root canal, but usually this won't last more than a few days to a week. If it's been longer than this, go back to your dentist.

Maybe: It is not uncommon to have post-op sensitivity after root canal therapy. If the tooth had an infection/abscess prior to treatment, the pain/infection will usually subside after 3-10 days by itself. If after 3 days things are not getting better, see the dentist who did the root canal for a possible antibiotic and/or stronger pain meds to get through the healing process.