The difference betweem SHIN SPLINTS and STRESS FRACTURES?

Can someone tell me what the sympthoms of both are and how i can tell the difference without going to the doctor right away?

Only a doctor can tell for sure. Usually you need a x-ray (though many stress fractures won't show up until they start healing), bone scan, or MRI to tell for sure whether it's shin splints or a stress fracture of the tibia.

There is also a problem known as Compartment Syndrome that can be confused with a stress fracture or shin splints. If your pain is more like a burning or numbness and tightness that comes on during exercise, it's possible you have Compartment Syndrome. Compartment syndrome is where your leg swells up and has no where to go; it needs to be evaluated by a doctor because it can effect the nerves and blood vessels in your feet. Also, although very rare, a bone tumor could also cause shin splint type pain. That's one good reason to check with a doc.

In general the differences between shin splints / stress fractures:

Shin splints will hurt over a larger area. With a stress fracture, you usually can find one small spot (often you can cover it with one finger) that hurts a lot if you press on it. The spot will be located right on the bone.

Shin splints often are worst when you first start exercising, then get better as you run/work out, only to usually come back at the end. Stress fractures will hurt more and more the longer you exercise, often to the point where it makes you have to stop.

Shin splints usually stop hurting once you stop exercising. A stress fracture will often hurt even after you stop exercising, including while walking and might even keep you up at night.

Stress fractures will often hurt if you walk up or down stairs. A quick test is if you can hop up and down on one foot on the effected leg ten times without causing severe pain, you probably don't have a stress fracture, but rather shin splints. If you had a stress fracture, it would be almost impossible to hop up and down like that without causing a lot of pain.

These are just some general differences. You can of course have stress fractures that are atypical. It's also worth noting that shin splints can sometimes develop into stress fractures if they are left untreated and you keep running/exercising on the effected leg.

Shin splints are swelling and inflammation of the muscles and other structures that are attached to the Tibia (the large bone in the lower leg.
Stress fractures are cracks in the bone itself . They can occur in almost any bone. More frequently in the foot and lower leg. They can be diagnosed by Xrays or MRIs.