Red painfull gum lump under root canal tooth

I had a root canal done all in one visit 5 weeks ago. The tooth is the second to last molar on my right side on the bottom. The tooth became painful 4 weeks after so I went back. Dentist told me my tooth had an infection inside. He redid the first part of the root canal. He told me he cleaned it out, put medication inside the tooth and placed a temp filling on it and have to come back in 2 weeks to finish it. It has been 8 days since then and the tooth is still alittle sore (completely cannot chew anything on that side of my mouth) but there is a red lump on my gum directly under the root canal tooth. The lump is extremely painful. Is this normal to have while the infection is clearing up? The painful lump was not there before this second visit to redo the root canal. During this redo visit The dentist did have to give me many Novocain shots in my jaw and directly into the gum to numb me, would that have anything to do with it?