Your angle grinder may be making noise because it is overworked. Machines, like humans, don’t function well after heavy loads for prolonged periods of time. It is recommended that you allow the device to spin freely after a moderate amount of difficult work before resuming your project. The angle grinder is fixable - visit the ‘overworking’ link on the troubleshooting page found here: Makita GA4030K Troubleshooting
The angle grinder may be low on grease or may have outside elements in the existing grease. Grease is meant to allow the internally moving parts to function with as little resistance as possible. When there’s a lot of strain on the grinder (resistance), it will get hot. The angle grinder is fixable - visit the ‘new grease’ link on the troubleshooting page found here: Makita GA4030K Troubleshooting
When you dropped the angle grinder, you may have dislodged or broken some internal components. To find the problem, open up the angle grinder and look for damage and loose pieces. Damage could take the form of dents, unconnected wires, or loose graphite bits within the device. The angle grinder is fixable - visit the ‘switch repair’ link on the troubleshooting page found here: Makita GA4030K Troubleshooting