If you have pain lifting above 90 degrees then that is almost always a rotator cuff tendon injury. The pain is due to the swollen tendon rubbing against the acromion (which does not normally happen when the tendon is not swollen)
My guesstimate from experience: 90% of the time that will heal with rest (2-4 weeks) and anti-inflammatories, eg ibuprofen. You should be able to buy ibuprofen or diclofenac (I personally prefer the latter for it's stronger anti-inflammatory action, although ibuprofen is stronger as a painkiller) from a pharmacy without a prescription. You can take it with paracetamol (aka acetaminophen/tylenol in North America) if the pain is unbearable, although a little pain is good - it forces you to be aware of the injury in your shoulder, preventing reinjury.
Also don't go straight back into the exercise with full intensity after recovery, build up the intensity.
If there is still some residual pain after the acute injury, shoulder mobility exercises should help. Something like this: http://www.youtube.com/watch?v=KoGtrEcsqPQ
If still having pain, at that point you may need a doctor or at least a physiotherapist.
My guesstimate from experience: 90% of the time that will heal with rest (2-4 weeks) and anti-inflammatories, eg ibuprofen. You should be able to buy ibuprofen or diclofenac (I personally prefer the latter for it's stronger anti-inflammatory action, although ibuprofen is stronger as a painkiller) from a pharmacy without a prescription. You can take it with paracetamol (aka acetaminophen/tylenol in North America) if the pain is unbearable, although a little pain is good - it forces you to be aware of the injury in your shoulder, preventing reinjury.
Also don't go straight back into the exercise with full intensity after recovery, build up the intensity.
If there is still some residual pain after the acute injury, shoulder mobility exercises should help. Something like this: http://www.youtube.com/watch?v=KoGtrEcsqPQ
If still having pain, at that point you may need a doctor or at least a physiotherapist.