I understand muscles can be sore after a workout the next day, yesterday I was benchpressing and today my left elbow feels kinda sore. This isn't the first time. It's also happened in my forearms, shoulder plate, then after a couple days it goes away. What's the reason? Same thing has happened to me after running in my knees or a leg workout. Am I going to injure myself?

Soreness is normal at first. After a few workouts though this should dissipate.
The elbows though sound like your using improper form. Are your elbows point towards your tows or more out to the side when bench pressing?

outwards, I'm guessing that's wrong. I have bad form in any exercise that I do, I started running about 2 miles a day after a couple weeks this was back in February and my left leg is still sore. I stopped running and my leg is still not healed, been to the doctor twice yesterday got x-rays done, and they say there's nothing wrong. They gave me a brace today that seems to help.

Here is a decent rundown on bench form that I personally like. Bodybuilding.com - Nick Nilsson - How To Do The Perfect Bench Press Rep!

Well If its not bone related then an X-ray would not show the damage. It could be some sort of tear in the muscle or possibly tendon.

Who do I go to find out if it's a tear in the muscle or not?

Your doctor will likely be the best bet. Simply state you have concern about a non bone (fracture) related injury to the location. He then "should" prescribe an MRI of the area to check.

I hardly go to the doctor, so I don't have a particular one I go to. So far I've been to two clinics, and I'm guessing this isn't the same as going to a doctor since, I'm paying to go there and see them and they don't do anything except have me move my leg to see if it's broken and prescribe me Ibuporfen. This last time they charged about $300 and said if the problem isn't fixed to come back again!

I shouldn't have to go there and pay them again for the 3rd time just to tell them that I think it's a torn muscle, isn't this something they should know themselves that it could be a possibility? I sure hope this third time is my last time, I'm going to have to make an appointment with a sports doctor like I should've the first time.

Yeah that sounds like a great idea!

Yeah I'm like you, I have no doctor either. Though as they said "come back if it ain't fixed!" They likely know what is bothering you they just want you to come back again so you can pay again...Not the first time I have seen "clinics" do that to people.

Just clean up your form a bit on benching, that should fix the elbow issue.
As far as pain from running, you ARE stretching and warming up a bit before a run, right? If not, yeah your knees and shins probably won't be too happy after a run. Is the pain bad enough that you limp or just some dull pain?

No, I didn't stretch but I did lots of walking to warm up. I've done the same thing on treadmills in the past and never had any problems. Ofcourse at that time I was running every other day. I think I just did too much, I've never ran 2 miles and started running daily. Although I do realize not stretching probably has to do with it, and should stretch before I run.

It doesn't make me limp but if I stand up or sit down it was really bad in the beginning, but has gotten much better, it's still there but not as much, but after 3-4 months I would think there shouldn't be any pain at all.