I Have A Lump Next To My Tailbone It Started

I have a lump next to my tailbone it started as just being sore so I thought it was from a small fall but over the week its been getting worse and now its a pretty big lump on the left side of my tail bone and a small lump to the right there's also abit of bruising that has only just showed up in the last 24 hours should I go to the doctors or will it just go away? Its hard to sit down and walk so I'm desperate for the pain to go