My heating system still runs, but it makes a lot of noise

However, just as the heating system randomly started screeching, the heating system stopped

My heating system still runs, but my heating system is also making a lot of noise. I have no method what is wrong with my heating system. I thought that my heating system was in great condition, then when I bought this house, the heating system was pretty old. I called an Heating as well as Air Conditioning professional, as well as I totally expected the Heating as well as Air Conditioning professional to tell myself and others that I was going to have to replace the heating system before we moved in. However, the Heating as well as Air Conditioning professional told myself and others that the heating system was in pretty nice shape, as well as he expected the heating system to last a few more years. It has been a few years, as well as the heating system was working well. I was absolutely bragging to all of my friends about how awesome this heating system was. However, the heating system is starting to act up, as well as I have no method why. One afternoon, while we were getting ready for bed, we began to hear this really loud screeching noise. Every one of us don’t have children or pets, so I had no method what this screeching noise was coming from. While I was looking around for the source of the loud noise, I discovered that it was absolutely coming from the heating system, for some reason, the heating system was making this bad noise. I tried turning the heating system off as well as back on again, but it didn’t stop the screeching sound. I even called 1 of my friends that have worked on Heating as well as Air Conditioning units before, as well as he confirmed that it was actually a pretty immense issue. However, just as the heating system randomly started screeching, the heating system stopped. Now, the heating system only does that randomly, although I suppose that it is getting more common. I am absolutely going to have to do something about my heating system.
Further information on AC