I had a root canal done a month ago and I’m having sensitivity when I bite down with no pain. Why?

I got it done a month ago. Half my tooth was cracked so the root canal was performed on the cracked tooth it took 1 week to heal but now I feel sensitivity when I put pressure on the tooth. There is no pain but once I touch the tooth with my finger it hurts ? Is this normal ? Did the root canal fail?
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