If your insurance will cover a visit to a podiatrist without requiring a referral from a GP, go directly to the podiatrist. My experience has been that they diagnose foot problems more quickly & accurately because they specialize in that. I had to go to a GP first for some foot fractures & plantar faciitis & they just ended up referring me to the podiatrist.
Your symptoms sound very similiar to the ones I had when I had plantar fasciitis (link below explaining). But it could be other things too, so see a podiatrist to be sure.
http://orthoinfo.aaos.org/topic.cfm?topic=A00149
Is it worse first thing in the morning and it gets better as the day goes on? That was the case with me. Also, have you had flat feet at any point in your life? People with that are more prone to it. And have you recently intensified training by going up hills? Tackling hills can cause flare ups because of the position it puts your feet in.
Mine wasn't too bad, I just did the ice/pain reliever thing & eased off a bit on activity until it felt better. Also, instead of going barefoot around the house (lifetime of apartment living training), I now wear either slippers with a wedged heel or flip flops with a wedged heel. If it plantar fasciitis, you'll want to make sure any footwear you wear has good arch support. And I did the recommended stretching exercises. I didn't have to get shots or surgery fortunately. It started acting up again when I tried the hill intervals on the arc climber & didn't stretch properly, I switched back to regular intervals & make sure I stretch now.
Another thing I was told was to watch road surfaces. Concrete is the toughest, grass, treadmills & asphalt are preferable to concrete. And to make sure shoes are cushioned to absorb impact. Some shoes are also designed to help with over-pronation if that's an issue (it is with me).