It may never return to normal. I had a quintuple 2 years ago at age 49. I still get odd little sensations and numb areas at times - the hard part is that from going through the whole heart related ordeal, I am very sensitive to anything that occurs in the chest area. It is easy to get alarmed.
It seems it takes about 6 months to fully recover...some individuals recover more slowly if they are diabetic, etc.
A few weeks, it's basically where the nerves are connecting back together. Mine started
off as a pain then turned into a stinging sensation to the touch after about three weeks.
The problem is, everyone experiences different levels of discomfort. If it feels that sore,
you could ask your gp to prescribe some pain relief such as that used for trapped nerves.