Swelled bump in center of chest..

Would epsom salt and warm water help reduce it?

No, I don't believe so. A hematoma is basically a bruise, but there was just so much blood that it had nowhere to disipaite, and so a membrane forms around it, creating a lump. In humans, hematomas can often just dissolve over time if its in an area of high blood traffic, or they can harden and become a fiberous mass like sara mentioned.

Treatment is often as simple as having a doctor remove the extra fluid with a syringe. Again, this is all in humans. I don't know if you mentioned this in the OP, but have you consulted a vet about your horses treatment?

No, just been searching online. I have a vet book and it says to try to shave it and wash several times with antibacterial soap and then apply DMSO and do that for 3 or 4 days

DMSO is a good one, test a patch of skin first to see how your horse will react to it as some are quite sensitive. Where will you be getting the DMSO from and what concentration is it? Also, you can massage the area every day to help dissipate the fluids.

Also important: Check to make sure there are no puncture sites or broken skin as the last thing you want with a hematoma is an infection as there is such a high risk of it becoming systemic. Check it every day for changes in size and temperature. If it gets suddenly bigger or hotter you MUST have a vet out. Whatever you do DON'T attempt to drain it yourself, this must be done by a vet as there is a high risk of infection.

Im going to get at least 90% or higher but im not sure as to get the solvent or gel. Which is better. I'm going to have to buy it online I can't find it anywhere around here

Liniment and massage with the warm water twice/day helps. Liniment you can get anywhere on-line. But if it's too costly I'd just go with warm water and massage. I had similar issue with my mare (except her swelling on chest was HUGE) and it went down in 2 weeks and disappeared in month.

P.S. Massage/warm water idea I found on internet somewhere was supported by my vet as well.

Ok thanks would green cool be a liniment?

I'm not positive what it is. Is that green stuff people put on horse's noses to prevent from sun burn? If you'd give the full name... I tried to google and couldn't find anything frankly.

Cool Pack?
Farnam Cool Pack Green Jelly Horse Liniment - Dover Saddlery.

No its a gell that you put on its the 6th item down it comes in a bottle. Its like blue heat (same type of bottle)

Liniments Horse Liniment Absorbine Liniment Sore No More Liniment